ECS Journal of Solid State Science and Technology

Open all abstracts, in this tab

• The following article is Open access
  A Review on the Fabrication and Manufacturing Processes of All-Solid-State Batteries From Laboratory Research to Industrial Scale-Up

  Han Cui and Shaofeng Kong 2026 ECS J. Solid State Sci. Technol. 15 033006

  View article, A Review on the Fabrication and Manufacturing Processes of All-Solid-State Batteries From Laboratory Research to Industrial Scale-UpPDF, A Review on the Fabrication and Manufacturing Processes of All-Solid-State Batteries From Laboratory Research to Industrial Scale-UpOpen abstract

  With the advancement of electric vehicle (EV) battery technologies, conventional lithium-ion batteries are approaching their theoretical energy density limits while facing persistent safety concerns. All-solid-state batteries (ASSBs) offer a pathway toward higher energy density and enhanced safety. This review focuses on the fabrication and manufacturing processes of ASSBs, explicitly bridging laboratory-scale research methods with emerging industrial-scale production routes. Emphasis is placed on material systems, scalable processing strategies, manufacturing bottlenecks, and industrial roadmaps.

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  https://doi.org/10.1149/2162-8777/ae5451
• The following article is Open access
  Review—Silicon Nitride and Silicon Nitride-Rich Thin Film Technologies: State-of-the-Art Processing Technologies, Properties, and Applications

  Alain E. Kaloyeros et al 2020 ECS J. Solid State Sci. Technol. 9 063006

  View article, Review—Silicon Nitride and Silicon Nitride-Rich Thin Film Technologies: State-of-the-Art Processing Technologies, Properties, and ApplicationsPDF, Review—Silicon Nitride and Silicon Nitride-Rich Thin Film Technologies: State-of-the-Art Processing Technologies, Properties, and ApplicationsOpen abstract

  Accelerating interest in silicon nitride thin film material system continues in both academic and industrial communities due to its highly desirable physical, chemical, and electrical properties and the potential to enable new device technologies. As considered here, the silicon nitride material system encompasses both non-hydrogenated (SiN_x) and hydrogenated (SiN_x:H) silicon nitride, as well as silicon nitride-rich films, defined as SiN_x with C inclusion, in both non-hydrogenated (SiN_x(C)) and hydrogenated (SiN_x:H(C)) forms. Due to the extremely high level of interest in these materials, this article is intended as a follow-up to the authors’ earlier publication [A. E. Kaloyeros, F. A. Jové, J. Goff, B. Arkles, Silicon nitride and silicon nitride-rich thin film technologies: trends in deposition techniques and related applications, ECS J. Solid State Sci. Technol., 6, 691 (2017)] that summarized silicon nitride research and development (R&D) trends through the end of 2016. In this survey, emphasis is placed on cutting-edge achievements and innovations from 2017 through 2019 in Si and N source chemistries, vapor phase growth processes, film properties, and emerging applications, particularly in heterodevice areas including sensors, biointerfaces and photonics.

  https://doi.org/10.1149/2162-8777/aba447
• The following article is Open access
  Review—Ionizing Radiation Damage Effects on GaN Devices

  S. J. Pearton et al 2016 ECS J. Solid State Sci. Technol. 5 Q35

  View article, Review—Ionizing Radiation Damage Effects on GaN DevicesPDF, Review—Ionizing Radiation Damage Effects on GaN DevicesOpen abstract

  Gallium Nitride based high electron mobility transistors (HEMTs) are attractive for use in high power and high frequency applications, with higher breakdown voltages and two dimensional electron gas (2DEG) density compared to their GaAs counterparts. Specific applications for nitride HEMTs include air, land and satellite based communications and phased array radar. Highly efficient GaN-based blue light emitting diodes (LEDs) employ AlGaN and InGaN alloys with different compositions integrated into heterojunctions and quantum wells. The realization of these blue LEDs has led to white light sources, in which a blue LED is used to excite a phosphor material; light is then emitted in the yellow spectral range, which, combined with the blue light, appears as white. Alternatively, multiple LEDs of red, green and blue can be used together. Both of these technologies are used in high-efficiency white electroluminescent light sources. These light sources are efficient and long-lived and are therefore replacing incandescent and fluorescent lamps for general lighting purposes. Since lighting represents 20–30% of electrical energy consumption, and because GaN white light LEDs require ten times less energy than ordinary light bulbs, the use of efficient blue LEDs leads to significant energy savings. GaN-based devices are more radiation hard than their Si and GaAs counterparts due to the high bond strength in III-nitride materials. The response of GaN to radiation damage is a function of radiation type, dose and energy, as well as the carrier density, impurity content and dislocation density in the GaN. The latter can act as sinks for created defects and parameters such as the carrier removal rate due to trapping of carriers into radiation-induced defects depends on the crystal growth method used to grow the GaN layers. The growth method has a clear effect on radiation response beyond the carrier type and radiation source. We review data on the radiation resistance of AlGaN/GaN and InAlN/GaN HEMTs and GaN–based LEDs to different types of ionizing radiation, and discuss ion stopping mechanisms. The primary energy levels introduced by different forms of radiation, carrier removal rates and role of existing defects in GaN are discussed. The carrier removal rates are a function of initial carrier concentration and dose but not of dose rate or hydrogen concentration in the nitride material grown by Metal Organic Chemical Vapor Deposition. Proton and electron irradiation damage in HEMTs creates positive threshold voltage shifts due to a decrease in the two dimensional electron gas concentration resulting from electron trapping at defect sites, as well as a decrease in carrier mobility and degradation of drain current and transconductance. State-of-art simulators now provide accurate predictions for the observed changes in radiation-damaged HEMT performance. Neutron irradiation creates more extended damage regions and at high doses leads to Fermi level pinning while ⁶⁰Co γ-ray irradiation leads to much smaller changes in HEMT drain current relative to the other forms of radiation. In InGaN/GaN blue LEDs irradiated with protons at fluences near 10¹⁴ cm⁻² or electrons at fluences near 10¹⁶ cm⁻², both current-voltage and light output-current characteristics are degraded with increasing proton dose. The optical performance of the LEDs is more sensitive to the proton or electron irradiation than that of the corresponding electrical performances.

  https://doi.org/10.1149/2.0251602jss
• The following article is Open access
  Origin and Innovations of CMP Slurry

  Hitoshi Morinaga 2024 ECS J. Solid State Sci. Technol. 13 074006

  View article, Origin and Innovations of CMP SlurryPDF, Origin and Innovations of CMP SlurryOpen abstract

  This paper reviews how today’s CMP (Chemical Mechanical Polishing) slurries have been innovated and explores ideas for driving further evolution. In early semiconductor polishing, Mechanical Polishing was used, focusing on controlling abrasive particle sizes, leading to the use of alumina abrasives via wet classification. As materials shifted from germanium to silicon and applications transitioned from radios to integrated circuits, research was conducted on the material and size of abrasives to improve polishing accuracy, and silica was finally adopted. Subsequently, in pursuit of higher purity, ultrapure colloidal silica using organic raw materials was introduced in 1985 and became the standard in current semiconductor CMP. The first report on CMP dates back to Schmidt’s 1962 paper. Although the report was based on visual inspection, the approach was validated to be reasonable with today’s inspection technology. CMP achieved further defect reduction by integrating with Clean Technology. Throughout its history, polishing consistently pursued uniform action on surfaces, driving contaminant reduction, and occasionally achieving significant breakthroughs through the combination of diverse technologies. Innovations are born when disparate technologies, evolving independently until a certain point, interact and combine according to market needs.

  https://doi.org/10.1149/2162-8777/ad5fb6
• The following article is Open access
  Review—ZnO-based Thin Film Metal Oxide Semiconductors and Structures: Transistors, Optoelectronic Devices and Future Sustainable Electronics

  Darragh Buckley et al 2025 ECS J. Solid State Sci. Technol. 14 015001

  View article, Review—ZnO-based Thin Film Metal Oxide Semiconductors and Structures: Transistors, Optoelectronic Devices and Future Sustainable ElectronicsPDF, Review—ZnO-based Thin Film Metal Oxide Semiconductors and Structures: Transistors, Optoelectronic Devices and Future Sustainable ElectronicsOpen abstract

  Metal oxide thin films are critically important materials for modern technologies, particularly semiconductor thin films in transistors and optoelectronic applications. Many metal oxide thin films attract interest for their electronic bandgap, charge carrier mobility, optical opacity, luminescence, low cost, relative abundance, and environmentally-friendly production. Additionally, these properties are often tuneable via particle size, film density, surface morphology, film deposition, growth method, hetero-interface engineering or ion-doping. The n-type semiconducting zinc oxide (ZnO) is an important material, possessing a variety of useful properties including an intrinsically wide direct bandgap, high electron mobility, relatively high exciton binding energy, high optical transparency, demonstrated metal-ion doping, a range of different particle morphologies and deposition methods, electro/photoluminescence, low cost, and a variety of existing green synthesis methods. Here, these aspects of ZnO and some related compound semiconducting oxides are reviewed, focusing on how the unique properties of these metal oxides make them suitable for a range of different applications from thin film transistors, high mobility oxide interfaces, transparent conductive oxides, photoanodes photodetectors, chemical sensors, photocatalysts, superlattice electronics, and more. The properties and deposition methods and their impact on functionality will be discussed alongside their role in sustainable optoelectronics.

  https://doi.org/10.1149/2162-8777/ada3a2
• The following article is Open access
  Void Formation Mechanism Related to Particles During Wafer-to-Wafer Direct Bonding

  F. Nagano et al 2022 ECS J. Solid State Sci. Technol. 11 063012

  View article, Void Formation Mechanism Related to Particles During Wafer-to-Wafer Direct BondingPDF, Void Formation Mechanism Related to Particles During Wafer-to-Wafer Direct BondingOpen abstract

  Achieving a void-free bonding interface is an important requirement for the wafer-to-wafer direct bonding process. The two main potential mechanisms for void formation at the interface are (i) void formation induced by gas, such as condensation by-products caused by the bonding process or outgassing of trapped precursors, and (ii) void formation induced by physical obstacles, such as particles. In this work, emphasis is on the latter process. Particles were intentionally deposited on the wafer prior to bonding to study the kinetics of the physical void formation process. Void formations induced by particles deposited on different dielectrics bonding materials were analyzed using scanning acoustic microscopy and image software. The void formation mechanism is then discussed along with the wafer bonding dynamics at room temperature.

  https://doi.org/10.1149/2162-8777/ac7662
• The following article is Open access
  Review—Betavoltaic Cell: The Past, Present, and Future

  Chunlin Zhou et al 2021 ECS J. Solid State Sci. Technol. 10 027005

  View article, Review—Betavoltaic Cell: The Past, Present, and FuturePDF, Review—Betavoltaic Cell: The Past, Present, and FutureOpen abstract

  In recent years, betavoltaic batteries have become an ideal power source for micro electromechanical systems. Betavoltaic battery is a device that converts the decay energy of beta emitting radioisotope sources into electrical energy using transducers. They have the advantages of high energy density, long service life, strong anti-interference ability, small size, light weight, easy miniaturization and integration, thus it has become a research hotspot in the field of micro energy. However, to date, the low energy conversion efficiencies as well as technological limitations of betavoltaic batteries impede their further application. In this review, the theory of betavoltaic energy conversion and recent understanding of the ideal material and structure design of the betavoltaic batteries for efficient exciton production, dissociation and charge transport is described, as well as recent attempts to realize optimum results. This review article concludes by identifying the remaining challenges for the improvement of battery performance and by providing perspectives toward real application of betavoltaic batteries.

  https://doi.org/10.1149/2162-8777/abe423
• The following article is Open access
  TCAD Simulation Models, Parameters, and Methodologies for β-Ga₂O₃ Power Devices

  Hiu Yung Wong 2023 ECS J. Solid State Sci. Technol. 12 055002

  View article, TCAD Simulation Models, Parameters, and Methodologies for β-Ga2O3 Power DevicesPDF, TCAD Simulation Models, Parameters, and Methodologies for β-Ga2O3 Power DevicesOpen abstract

  β-Ga₂O₃ is an emerging material and has the potential to revolutionize power electronics due to its ultra-wide-bandgap (UWBG) and lower native substrate cost compared to Silicon Carbide and Gallium Nitride. Since β-Ga₂O₃ technology is still not mature, experimental study of β-Ga₂O₃ is difficult and expensive. Technology-Computer-Aided Design (TCAD) is thus a cost-effective way to study the potentials and limitations of β-Ga₂O₃ devices. In this paper, TCAD parameters calibrated to experiments are presented. They are used to perform the simulations in heterojunction p-NiO/n-Ga₂O₃ diode, Schottky diode, and normally-off Ga₂O₃ vertical FinFET. Besides the current-voltage (I-V) simulations, breakdown, capacitance-voltage (C-V), and short-circuit ruggedness simulations with robust setups are discussed. TCAD Sentaurus is used in the simulations but the methodologies can be applied in other simulators easily. This paves the road to performing a holistic study of β-Ga₂O₃ devices using TCAD.

  https://doi.org/10.1149/2162-8777/accfbe
• The following article is Open access
  Editors' Choice—Review—Theory and Characterization of Doping and Defects in β-Ga₂O₃

  Marko J. Tadjer et al 2019 ECS J. Solid State Sci. Technol. 8 Q3187

  View article, Editors' Choice—Review—Theory and Characterization of Doping and Defects in β-Ga2O3PDF, Editors' Choice—Review—Theory and Characterization of Doping and Defects in β-Ga2O3Open abstract

  Gallium oxide (β-Ga₂O₃) is an emerging semiconductor with relevant properties for power electronics, solar-blind photodetectors, and some sensor applications due to its ultra-wide bandgap and developing technology base for high quality, melt-based substrate growth and thick, low-doped homoepitaxial layers. Of critical importance for the commercialization of this potentially important material is understanding of doping mechanisms in the monoclinic lattice, where two types of Ga sites and three types of O sites have been identified. A critical literature review of doping and defects of the monoclinic β-phase of gallium oxide is provided in this work. Theoretical fundamentals of both donor and acceptor doping in Ga₂O₃ are reviewed. Advances in doping of epitaxial Ga₂O₃ with a focus on molecular beam epitaxy and ion implantation are critically examined. As doping is fundamentally related to defects, particularly in this material, a review of defect characterization by optical and electrical spectroscopic methods is provided as well. P-type doping, one of the fundamental challenges for Ga₂O₃, is discussed in terms of first-principles calculations and ion implantation of known acceptors such as Mg and N.

  https://doi.org/10.1149/2.0341907jss
• The following article is Open access
  Origin of Voids at the SiO₂/SiO₂ and SiCN/SiCN Bonding Interface Using Positron Annihilation Spectroscopy and Electron Spin Resonance

  F. Nagano et al 2023 ECS J. Solid State Sci. Technol. 12 033002

  View article, Origin of Voids at the SiO2/SiO2 and SiCN/SiCN Bonding Interface Using Positron Annihilation Spectroscopy and Electron Spin ResonancePDF, Origin of Voids at the SiO2/SiO2 and SiCN/SiCN Bonding Interface Using Positron Annihilation Spectroscopy and Electron Spin ResonanceOpen abstract

  To obtain reliable 3D stacking, a void-free bonding interface should be obtained during wafer-to-wafer direct bonding. Historically, SiO₂ is the most studied dielectric layer for direct bonding applications, and it is reported to form voids at the interface. Recently, SiCN has raised as a new candidate for bonding layer. Further understanding of the mechanism behind void formation at the interface would allow to avoid bonding voids on different dielectrics. In this study, the void formation at the bonding interface was studied for a wafer pair of SiO₂ and SiCN deposited by plasma enhanced chemical vapor deposition (PECVD). The presence of voids for SiO₂ was confirmed after the post-bond anneal (PBA) at 350 °C by Scanning Acoustic Microscopy. Alternatively, SiCN deposited by PECVD has demonstrated a void-free interface after post bond annealing. To better understand the mechanism of void formation at the SiO₂ bonding interface, we used Positron Annihilation Spectroscopy (PAS) to inspect the atomic-level open spaces and Electron Spin Resonance (ESR) to evaluate the dangling bond formation by N₂ plasma activation. By correlating these results with previous results, a model for void formation mechanism at the SiO₂ and the absence of for SiCN bonding interface is proposed.

  https://doi.org/10.1149/2162-8777/acbe18

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• Corrigendum: Defect-Oriented 2D Nanocomposites as Flexible Piezoelectric Nanogenerators: Encapsulation Effect [ECS J. Solid State Sci. Technol., 10, 071005 (2021)]

  Pooja Shukla et al 2026 ECS J. Solid State Sci. Technol. 15 079001

  View article, Corrigendum: Defect-Oriented 2D Nanocomposites as Flexible Piezoelectric Nanogenerators: Encapsulation Effect [ECS J. Solid State Sci. Technol., 10, 071005 (2021)]PDF, Corrigendum: Defect-Oriented 2D Nanocomposites as Flexible Piezoelectric Nanogenerators: Encapsulation Effect [ECS J. Solid State Sci. Technol., 10, 071005 (2021)]
  https://doi.org/10.1149/2162-8777/ae8697
• Chemical Mechanical Polishing on Silicon Wafers Using Lysine-Catalyzed Synthesis of Silica Abrasives with High Efficiency

  Wenqing Jia et al 2026 ECS J. Solid State Sci. Technol. 15 074002

  View article, Chemical Mechanical Polishing on Silicon Wafers Using Lysine-Catalyzed Synthesis of Silica Abrasives with High EfficiencyPDF, Chemical Mechanical Polishing on Silicon Wafers Using Lysine-Catalyzed Synthesis of Silica Abrasives with High EfficiencyOpen abstract

  Although environmentally benign chemical mechanical polishing (CMP) systems have attracted increasing attention, simultaneously achieving high material removal efficiency, atomic-level surface quality, and low additive concentration remains challenging. In this work, a sustainable silicon CMP slurry was developed by integrating lysine-derived monodisperse SiO₂ abrasives with the organo-superbase 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and glycine (Gly). Owing to its strong basicity, DBU enables efficient silicon oxidation at substantially reduced additive concentration, while Gly improves slurry stability and interfacial chemical–mechanical interactions. The optimized slurry containing 2.0 wt.% 85 nm SiO₂, 0.5 wt.% DBU, and 0.5 wt.% Gly achieved an ultra-smooth silicon surface with a roughness average (Ra) of 0.153 nm and a material removal rate (MRR) of 163.42 nm min⁻¹, outperforming a commercial slurry (Ra = 0.953 nm, MRR = 136.82 nm min⁻¹ ). Electrochemical and spectroscopic analyses revealed that DBU accelerates silicon oxidation, whereas Gly stabilizes the slurry and facilitates favorable interfacial reactions during polishing. The developed slurry provides a promising strategy for sustainable and high-precision silicon CMP.

  Highlights

  • An environmentally friendly lysine-catalyzed route is developed for the controllable synthesis of monodispersed silica abrasives.

  • The organo-superbase DBU is introduced as a powerful additive for the first time, drastically boosting the polishing rate with high efficiency.

  • Glycine is demonstrated to effectively enhance slurry stability and final surface quality via interfacial hydrogen bonding.

  • The superior polishing performance is evidenced by achieving an ultrasmooth surface with a roughness of 0.153 nm.

  • The synergistic effect between DBU and glycine facilitates Si–N bond formation, providing a novel strategy for high-efficiency CMP.

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  https://doi.org/10.1149/2162-8777/ae87cc
• Precise Control of Wafer Edge Removal Profile in Chemical Mechanical Polishing

  Takashi Fujita 2026 ECS J. Solid State Sci. Technol. 15 074001

  View article, Precise Control of Wafer Edge Removal Profile in Chemical Mechanical PolishingPDF, Precise Control of Wafer Edge Removal Profile in Chemical Mechanical PolishingOpen abstract

  Precise control of polishing approximately 1 mm from the edge of an oxide film on a silicon wafer requires secure wafer fixation in the chuck to correct warpage and rigid alignment of the retainer ring relative to the wafer. Stable edge polishing therefore depends strongly on accurately setting the retainer ring gap and height. In this study, material removal near the wafer edge was evaluated under conditions in which the relative positions of the wafer and retainer ring were fixed using a polishing pad mechanism supported by an elastic material. This configuration enabled independent examination of the effects of retainer height and gap on edge removal behavior. At a position 1 mm from the wafer edge, increasing the retainer height by 1 µm reduced the removal amount by approximately 45 nm, whereas increasing the retainer gap by 1 mm increased the removal amount by 555 nm. Both parameters exhibited a significant influence on edge material removal. These findings demonstrate that precise adjustment and control of retainer ring height and gap are essential for achieving stable polishing performance and a well defined wafer edge profile.

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  https://doi.org/10.1149/2162-8777/ae8330
• Optical Dispersion and Frequency Dependent Dielectric Behaviour of Monoclinic 1,4-Diazo Bicyclo[2.2.2]Octyl Benzoate (DBOB) Single Crystals

  D Dulasimathi et al 2026 ECS J. Solid State Sci. Technol. 15 073008

  View article, Optical Dispersion and Frequency Dependent Dielectric Behaviour of Monoclinic 1,4-Diazo Bicyclo[2.2.2]Octyl Benzoate (DBOB) Single CrystalsPDF, Optical Dispersion and Frequency Dependent Dielectric Behaviour of Monoclinic 1,4-Diazo Bicyclo[2.2.2]Octyl Benzoate (DBOB) Single CrystalsOpen abstract

  A single crystal of 1,4-Diazo Bicyclo [2.2.2] Octyl Benzoate (DBOB) was investigated to understand its structural, optical, dielectric, surface and chemical state properties. Single crystal X-ray diffraction confirms that the material crystallizes in the monoclinic system with space group P2₁/n, indicating a stable crystal framework. Optical studies carried out in the wavelength range of 200–1000 nm shows a transparency of 55% in the visible region. The optical band gap is estimated to be 4 eV. The evaluated optical parameters, including refractive index, extinction coefficient, optical conductivity and susceptibility, indicate stable interaction with UV–visible radiation. The dielectric response exhibits a strong dependence on frequency and temperature (308–368 K), with a decrease in dielectric constant at higher frequencies and a low dielectric loss, indicating minimal energy dissipation. AC conductivity follows Arrhenius behaviour, with activation energy decreasing from 0.96 eV to 0.10 eV, suggesting a transition from long range charge transport to localized hopping conduction. Morphological analysis reveals a heterogeneous surface composed of spherical, plate-like, and aggregated particles, with sizes ranging from 0.2 to 1.2 μm and an average size 0.43 μm. The corresponding 3D surface profile shows height variations of 0–250 units, indicating moderate surface roughness. XPS analysis confirms the presence of Carbon (284.9 eV), Nitrogen (400.8 eV), and Oxygen (531 eV) in their respective chemical states, supported by elemental composition values of Carbon (73.51%), Nitrogen (10.09%), and Oxygen (16.40%). These combined results indicate that DBOB exhibits stable optical and dielectric properties, suggesting its potential for dielectric and electronic applications.

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  https://doi.org/10.1149/2162-8777/ae8698
• The following article is Open access
  Electron Beam Irradiation-Induced Transport and Recombination in P-type Diamond Diodes

  Gabriel P Marciaga et al 2026 ECS J. Solid State Sci. Technol. 15 075004

  View article, Electron Beam Irradiation-Induced Transport and Recombination in P-type Diamond DiodesPDF, Electron Beam Irradiation-Induced Transport and Recombination in P-type Diamond DiodesOpen abstract

  This study investigates minority carrier diffusion length (L) and defect-mediated recombination phenomena in boron-doped p-type diamond epitaxial layers. Utilizing temperature-dependent electron beam-induced current (EBIC) and cathodoluminescence (CL), the influence of temperature and sustained electron beam irradiation was characterized. The diamond sample demonstrates a pronounced thermal enhancement to the minority carrier diffusion length. This temperature enhancement for L has an activation energy of 177 meV. Furthermore, sustained electron injection induces a near-linear elongation of the diffusion length through passivation of deep-level defects. From the EBIC injection data, an activation energy of 151 meV was extracted from fitting. Temperature-resolved CL reveals the quenching of the characteristic A-band emission at 100 °C. Additionally, a thermal activation energy of 112 meV was extracted via a decay fit of the temperature dependent CL intensity data. While sustained electron beam irradiation reveals dose-dependent quenching of the A-band emission with thermally activated decay rates. This yields activation energies of 110 meV and 11 meV associated with distinct defect generation mechanisms at high and low temperatures, respectively. This provides a complementary assessment of the defect landscape governing minority carrier lifetimes in these boron-doped diamond diodes.

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  https://doi.org/10.1149/2162-8777/ae87cd

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• Influence of Complexing Agents on the Material Removal Rate Selectivity in CMP for Copper Interconnects

  Jiaji Geng et al 2026 ECS J. Solid State Sci. Technol. 15 064003

  View article, Influence of Complexing Agents on the Material Removal Rate Selectivity in CMP for Copper InterconnectsPDF, Influence of Complexing Agents on the Material Removal Rate Selectivity in CMP for Copper InterconnectsOpen abstract

  Copper (Cu) interconnects are extensively employed in the manufacturing of integrated circuits. During the chemical mechanical polishing (CMP) process of these interconnects, precise control over the material removal selectivity between copper and barrier layers, such as tantalum/tantalum nitride (Ta/TaN), cobalt (Co), and ruthenium (Ru), is essential. As a critical component in CMP slurries, complexing agents play a direct role in regulating this selectivity by forming coordination bonds with copper and barrier-layer metals. This paper provides a systematic review of the mechanisms of commonly used complexing agents in CMP, classifying them into five categories: carboxylic acids, amines, organic acids, inorganic salts, and macromolecular polymer complexing agents. It focuses on elucidating their respective action mechanisms and current limitations in the removal of copper and barrier-layer metals. The review aims to offer valuable insights for future research and technological advances in related fields, as well as a theoretical foundation for achieving more efficient and controllable CMP processes.

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  https://doi.org/10.1149/2162-8777/ae70a8
• Evolution of Emerging Transistor Technologies Toward Quantum Devices in Nanoelectronics

  M. Balasubrahmanyam et al 2026 ECS J. Solid State Sci. Technol. 15 055005

  View article, Evolution of Emerging Transistor Technologies Toward Quantum Devices in NanoelectronicsPDF, Evolution of Emerging Transistor Technologies Toward Quantum Devices in NanoelectronicsOpen abstract

  Transistor Technology plays a crucial role in human life. The aim is to increase the number of applications and increase speed in a single Integrated Circuit (IC) of Transistor Technology. This paper reviews the conventional transistor devices (Planar MOSFET, MESFET, DGMOSFET, DGMOSFET with Dual Material, and DGMOSFET with High-k Materials), modern transistor devices (FinFET and SOI FinFET), and advanced transistor devices (GAAFET (Gate All Around Nanosheet FET, Gate All around Nanowire FET and Tree FET). Different aspects, such as Drain Induced Barrier Leakage (DIBL), Leakage Current, Short Channel Effects (SCE), and Subthreshold Swing (SS), influence the performance of FETs. A comparison study shows that the Nanosheet Field Effect Transistor (NSFET) is the best transistor device in the semiconductor industry due to its low power performance, and also provides low parasitic capacitance, low temperature sensitivity, better electrostatic control, higher switching capacity, and good considerable scaling. The review also explores the development of next-generation transistor architectures such as Forksheet FETs, Complementary FETs, Vertical Transport FETs, Quantum Dot Transistors, Single-Electron Transistors, and Qubit Devices, which are among the most promising candidates under active research and are being considered as potential replacements for nanosheet FETs.

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  Highlights

  • This paper reviews the conventional transistor devices (Planar MOSFET, DGMOSFET, etc), modern transistor devices (FinFET and SOI FinFET), and advanced transistor devices (GAAFET (Gate All Around Nanosheet FET, Gate All around Nanowire FET and Tree FET).

  • A comparison study shows that the Nanosheet Field Effect Transistor (NSFET) is the best transistor device in the semiconductor industry due to its low power performance, and also provides low parasitic capacitance, better electrostatic control, and good considerable scaling.

  • The review also explores the development of next-generation transistor architectures such as Forksheet FETs, Complementary FETs, Vertical Transport FETs, Quantum Dot Transistors, Single-Electron Transistors, and Qubit Devices, which are among the most promising candidates under active research and are being considered as potential replacements for nanosheet FETs.

  https://doi.org/10.1149/2162-8777/ae6a6c
• The following article is Open access
  A Review on the Fabrication and Manufacturing Processes of All-Solid-State Batteries From Laboratory Research to Industrial Scale-Up

  Han Cui and Shaofeng Kong 2026 ECS J. Solid State Sci. Technol. 15 033006

  View article, A Review on the Fabrication and Manufacturing Processes of All-Solid-State Batteries From Laboratory Research to Industrial Scale-UpPDF, A Review on the Fabrication and Manufacturing Processes of All-Solid-State Batteries From Laboratory Research to Industrial Scale-UpOpen abstract

  With the advancement of electric vehicle (EV) battery technologies, conventional lithium-ion batteries are approaching their theoretical energy density limits while facing persistent safety concerns. All-solid-state batteries (ASSBs) offer a pathway toward higher energy density and enhanced safety. This review focuses on the fabrication and manufacturing processes of ASSBs, explicitly bridging laboratory-scale research methods with emerging industrial-scale production routes. Emphasis is placed on material systems, scalable processing strategies, manufacturing bottlenecks, and industrial roadmaps.

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  https://doi.org/10.1149/2162-8777/ae5451
• Graphene as a Biomedical Material: Potentials and Perspectives

  Priyanka Mahajan et al 2026 ECS J. Solid State Sci. Technol. 15 011002

  View article, Graphene as a Biomedical Material: Potentials and PerspectivesPDF, Graphene as a Biomedical Material: Potentials and PerspectivesOpen abstract

  Biomedical procedures needed to be upgraded with time through various innovative techniques in order to enhance its efficacy. Graphene’s transformative potential in biomedicine owing to its unique physicochemical properties provides innovative platform in this regard. The current review begins with highlights on key attributes of graphene such as biocompatibility, surface functionalization potential, mechanical strength, and electrical/thermal conductivity. Further emphasis has been given to the graphene’s diverse roles, including nanocarriers for drug delivery, stimuli-responsive and targeted therapeutic strategies, biosensors for biomarker detection and their integration into wearable devices, and significant contributions to tissue engineering as well as regenerative medicine through scaffolds. Besides, its applications in bioimaging (MRI, fluorescence) and photothermal/photodynamic therapies are also discussed. Later part of review involves in vitro/in vivo biocompatibility and dose-dependent toxicity of graphene. Conclusively, the major challenges obstructing graphene-derivatives in biomedical applications are highlighted along with possible measures. Integration with emerging trends like AI and ML- empowered devices can underscore graphene’s promising role in next-generation biomedical platforms.

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  https://doi.org/10.1149/2162-8777/ae31ab
• Nanomaterial-Engineered Solid-State Sensors: Advances in Metal Oxides, MXenes, and Sustainable Electronics

  Prachi Palta et al 2025 ECS J. Solid State Sci. Technol. 14 127002

  View article, Nanomaterial-Engineered Solid-State Sensors: Advances in Metal Oxides, MXenes, and Sustainable ElectronicsPDF, Nanomaterial-Engineered Solid-State Sensors: Advances in Metal Oxides, MXenes, and Sustainable ElectronicsOpen abstract

  Recent developments in nano-materials have re-architected the frontiers of solid-state sensor design, enabling high sensitivity, selectivity, and sustainability across a broad spectrum of real-world applications. This review summarises the advances in nanomaterial-engineered sensors, including the connection between material structure and functional mechanisms, as well as the device’s performance. Doped metal-oxide semiconductors (SnO₂ or ZnO, or WO₃) or polyoxometalates or MXenes exhibit an improved speed of charge transfer, low temperatures, and selectivity. Hydrophilic polymers, biocomposites and MXene hybrid sensors based on impedance and ionic humidity are flexible, fast-reactive and self-powered. Piezoelectric and photoacoustic transduction, based on ferroelectric ceramics, PVDF, and bio-based polymers such as PLA, chitosan, and cellulose, provides a platform for sustainable and energy-harvesting wearable devices and implants. The combination of electrochemical materials and biodegradable materials also enhances environmentally friendly sensor technologies. Multimodal sensing is adopting new architectures developed using adaptive calibration and intelligent data interpretation based on new artificial intelligence. As observed in the review, the compositional tuning, heterostructuring, and nanoscale morphology are used to control the science of bridge materials and the engineering of functional devices. The vision for this area is to develop fully autonomous, power-driven, and recyclable sensor ecosystems that can seamlessly integrate into Internet of Things (IoT) networks, enabling continuous monitoring of the environment, health, and industrial status with minimal human intervention and environmental impact. Lastly, the existing challenges, such as interference from humidity, signal drift, and the possibility of large-scale manufacturability, are not only documented but also addressed through the opportunities presented by multifunctional sensor systems, autonomous sensor systems, and recyclable sensor systems of the future. Future developmental trends include the integration of machine learning algorithms with multimodal sensor arrays to provide real-time adaptive analytics, the development of biodegradable and bioresorbable platforms for transient implantable diagnostics, and the development of flexible, skin-conformal architectures for precision medicine and personalized wearable health monitoring. This comprehensive evaluation offers a unique perspective on how nanomaterial-engineered solid-state sensors can be utilized to support the development of next-generation, sustainable, and intelligent technologies.

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  https://doi.org/10.1149/2162-8777/ae2c1c

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• The following article is Open access
  Editors’ Choice—Structural, Electrical, and Luminescent Properties of Orthorhombic κ-Ga₂O₃ Grown by Epitaxial Lateral Overgrowth

  V. I. Nikolaev et al 2023 ECS J. Solid State Sci. Technol. 12 115001

  View article, Editors’ Choice—Structural, Electrical, and Luminescent Properties of Orthorhombic κ-Ga2O3 Grown by Epitaxial Lateral OvergrowthPDF, Editors’ Choice—Structural, Electrical, and Luminescent Properties of Orthorhombic κ-Ga2O3 Grown by Epitaxial Lateral OvergrowthOpen abstract

  The properties of orthorhombic κ-Ga₂O₃ films grown by Epitaxial Lateral Overgrowth (ELOG) were studied by Scanning Transmission Electron Microscopy (STEM), X-ray diffraction, capacitance-voltage profiling, Microcathodoluminescence (MCL) spectroscopy and imaging. ELOG mask was formed by deposition of SiO₂ stripes on TiO₂ buffer prepared on basal plane sapphire, with the stripes going along the [11$\mathop{2}\limits^{\unicode{x00305}}$0] direction of sapphire. κ-Ga₂O₃ ELOG growth was performed using Halide Vapor Phase Epitaxy (HVPE), with ELOG wing of the structure formed by lateral overgrowth over the 20 μm-wide SiO₂ stripes, while growth in between the stripes proceeded initially by vertical growth in the 5-μm-wide windows. TEM analysis showed that the material in the windows comprised 120^o rotational nanodomains typical of κ-Ga₂O₃, while, in the wing regions, the material was single-domain monocrystalline. The films were conducting, with the net donor density close to 10¹³ cm⁻³. The data suggested the material in the windows have much higher resistance than in the wings. MCL spectra and imaging revealed much higher density of nonradiative recombination centers in the windows than in the wings.

  https://doi.org/10.1149/2162-8777/ad0888
• The following article is Open access
  Editors’ Choice—Atomic Layer Etching of Tungsten Disulfide Using Remote Plasma-Induced Oxidation and Wet Etching

  Younghyun You et al 2023 ECS J. Solid State Sci. Technol. 12 075009

  View article, Editors’ Choice—Atomic Layer Etching of Tungsten Disulfide Using Remote Plasma-Induced Oxidation and Wet EtchingPDF, Editors’ Choice—Atomic Layer Etching of Tungsten Disulfide Using Remote Plasma-Induced Oxidation and Wet EtchingOpen abstract

  WS₂ is an emerging semiconductor with potential applications in next-generation device architecture owing to its excellent electrical and physical properties. However, the presence of inevitable surface contaminants and oxide layers limits the performance of WS₂-based field-effect transistors (FETs); therefore, novel methods are required to restore the pristine WS₂ surface. In this study, the thickness of a WS₂ layer was adjusted and its surface was restored to a pristine state by fabricating a recessed-channel structure through a combination of self-limiting remote plasma oxidation and KOH solution etching processes. The reaction between the KOH solution and WO_X enabled layer-by-layer thickness control as the topmost oxide layer was selectively removed during the wet-etching process. The thickness of the WS₂ layer decreased linearly with the number of recess cycles, and the vertical etch rate was estimated to be approximately 0.65 nm cycle⁻¹. Micro-Raman spectroscopy and high-resolution transmission electron microscopy revealed that the layer-by-layer etching process had a nominal effect on the crystallinity of the underlying WS₂ channel. Finally, the pristine state was recovered by removing ambient molecules and oxide layers from the surface of the WS₂ channel, which resulted in a high-performance FET with a current on/off ratio greater than 10⁶. This method, which provides a facile approach to restoring the pristine surfaces of transition-metal dichalcogenide (TMDC) semiconductors with precise thickness control, has potential applications in various fields such as TMDC-based (opto)electronic and sensor devices.

  https://doi.org/10.1149/2162-8777/ace6d5
• The following article is Open access
  Editors’ Choice—Thin Film Transistor Response in the THz Range

  M. S. Shur et al 2023 ECS J. Solid State Sci. Technol. 12 035008

  View article, Editors’ Choice—Thin Film Transistor Response in the THz RangePDF, Editors’ Choice—Thin Film Transistor Response in the THz RangeOpen abstract

  Novel metal oxide materials such as InGaZnO (IGZO), ZnO, SnO, and In₂O₃ and improved fabrication processes dramatically enhanced the achieved and projected thin film transistor (TFT) performance. The record values of the effective field-effect mobility of Metal Oxide TFT (MOTFT) materials have approached 150 cm²/Vs. We report on an improved compact TFT model based on three models: the RPI TFT model, the unified charge control model (UCCM), and the multi-segment TFT compact model. This improved model accounts for a non-exponential slope in the subthreshold regime by introducing a varying subthreshold slope and accounts for non-trivial capacitance dependence on the gate bias, and parasitic impedances. The analysis of the TFT response using this model and the analytical calculations showed that TFTs could have a significant response to impinging THz and sub-THz radiation. Using a complementary inverter and the phase-matched THz signal feeding significantly improves the detection sensitivity.

  https://doi.org/10.1149/2162-8777/acc20d
• The following article is Open access
  Editors’ Choice—Vibrational Properties of Oxygen-Hydrogen Centers in H⁺- and D⁺-Implanted Ga₂O₃

  Amanda Portoff et al 2020 ECS J. Solid State Sci. Technol. 9 125006

  View article, Editors’ Choice—Vibrational Properties of Oxygen-Hydrogen Centers in H+- and D+-Implanted Ga2O3PDF, Editors’ Choice—Vibrational Properties of Oxygen-Hydrogen Centers in H+- and D+-Implanted Ga2O3Open abstract

  The ion implantation of H⁺ and D⁺ into Ga₂O₃ produces several O–H and O–D centers that have been investigated by vibrational spectroscopy. These defects include the dominant V_Ga(1)-2H and V_Ga(1)-2D centers studied previously along with additional defects that can be converted into this structure by thermal annealing. The polarization dependence of the spectra has also been analyzed to determine the directions of the transition moments of the defects and to provide information about defect structure. Our experimental results show that the implantation of H⁺ (or D⁺) into Ga₂O₃ produces two classes of defects with different polarization properties. Theory finds that these O–H (or O–D) centers are based on two shifted configurations of a Ga(1) vacancy that trap H (or D) atom(s). The interaction of V_Ga(1)-nD centers with other defects in the implanted samples has also been investigated to help explain the number of O–D lines seen and their reactions upon annealing. Hydrogenated divacancy V_Ga(1)-V_O centers have been considered as an example.

  https://doi.org/10.1149/2162-8777/abd458
• The following article is Open access
  Editors’ Choice—Precipitation of Suboxides in Silicon, their Role in Gettering of Copper Impurities and Carrier Recombination

  G. Kissinger et al 2020 ECS J. Solid State Sci. Technol. 9 064002

  View article, Editors’ Choice—Precipitation of Suboxides in Silicon, their Role in Gettering of Copper Impurities and Carrier RecombinationPDF, Editors’ Choice—Precipitation of Suboxides in Silicon, their Role in Gettering of Copper Impurities and Carrier RecombinationOpen abstract

  This paper describes a theoretical investigation of the phase composition of oxide precipitates and the corresponding emission of self-interstitials at the minimum of the free energy and their evolution with increasing number of oxygen atoms in the precipitates. The results can explain the compositional evolution of oxide precipitates and the role of self-interstitials therein. The formation of suboxides at the edges of SiO₂ precipitates after reaching a critical size can explain several phenomena like gettering of Cu by segregation to the suboxide region and lifetime reduction by recombination of minority carriers in the suboxide. It provides an alternative explanation, based on minimized free energy, to the theory of strained and unstrained plates. A second emphasis was payed to the evolution of the morphology of oxide precipitates. Based on the comparison with results from scanning transmission electron microscopy the sequence of morphology evolution of oxide precipitates was deduced. It turned out that it is opposite to the sequence assumed until now.

  https://doi.org/10.1149/2162-8777/aba0ce

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• Photoluminescence Imaging for Defect Mapping and Quality Control of Al-Polar AlN Substrates

  Hargus et al 

  View accepted manuscript, Photoluminescence Imaging for Defect Mapping and Quality Control of Al-Polar AlN SubstratesPDF, Photoluminescence Imaging for Defect Mapping and Quality Control of Al-Polar AlN SubstratesOpen abstract

  In this work, sub-bandgap photoluminescence imaging is presented as a means with which to identify defect bands in bulk AlN. Sub-bandgap photoluminescence spectroscopy revealed large variations across different points in the mid-gap between 1.8 and 3.8eV, which was subsequently investigated using broad-area photoluminescence imaging. Two different LEDs (340 and 450nm) were used to spatially identify defect bands present in the UV and visible ranges. Bandpass filters were used at wavelengths between 450 and 700nm to further deconvolve bands of interest at different wafer points. Raman spectroscopy was performed at each wafer point to ensure that changes in the photoluminescence were not due to the presence of different phases or low crystal quality. These measurements revealed E2 (high) peaks with full-width half maximum (FWHM) values below 10cm-1 at all measured points, suggesting a high degree of crystallinity at all points, as would be expected with high quality bulk substrates. This confirmed that the substrates were of high quality and phase uniform across the entire wafer surface.

  https://doi.org/10.1149/2162-8777/ae8cbd
• Corrigendum: Graphene Nano-Engineered Plasma-Tailored Dielectric Interfaced (GNPTD) Field-Effect Transistor for Ultrasensitive Detection of Breast Cancer Biomarkers [ECS J. Solid State Sci. Technol., 15, 053007 (2026)]

  Yadav et al 

  View accepted manuscript, Corrigendum: Graphene Nano-Engineered Plasma-Tailored Dielectric Interfaced (GNPTD) Field-Effect Transistor for Ultrasensitive Detection of Breast Cancer Biomarkers [ECS J. Solid State Sci. Technol., 15, 053007 (2026)]PDF, Corrigendum: Graphene Nano-Engineered Plasma-Tailored Dielectric Interfaced (GNPTD) Field-Effect Transistor for Ultrasensitive Detection of Breast Cancer Biomarkers [ECS J. Solid State Sci. Technol., 15, 053007 (2026)]Open abstract

  The present work is a collusion of a Graphene Nano-engineered Plasma-Tailored Dielectric Interfaced (GNPTD) Field-Effect Transistor for Ultrasensitive Detection of Breast Cancer Biomarkers. The design proposed has been juxtaposed systematically with the traditional Silicon-Integrated Nano-engineered Plasma-Tailored Dielectric (SINPTD) FET to have the latter serve as a benchmark of evaluation and comparison. The sensor's response simulation for specific breast cell types- MCF-10A (ꜫr=4.5), Hs578T (ꜫr=22), and T47D (ꜫr=32)-has been done with a baseline of a conventional silicon-channel MOSFET.

  https://doi.org/10.1149/2162-8777/ae8938
• The following article is Open access
  Chemical Mechanical Polishing of In-Situ-Doped Polysilicon for MEMS Applications

  Pares et al 

  View accepted manuscript, Chemical Mechanical Polishing of In-Situ-Doped Polysilicon for MEMS ApplicationsPDF, Chemical Mechanical Polishing of In-Situ-Doped Polysilicon for MEMS ApplicationsOpen abstract

  This work presents a 200 mm wafer-scale single step industrial Chemical Mechanical Polishing (CMP) process to polish in-situ doped polysilicon using a commercial silica-based slurry. By tuning CMP operating conditions and pad conditioning, the surface roughness is reduced uniformly across the wafer down to Rq = 0.22 nm. Roughness reduction, is primarily driven by surface chemical reactions. Using gentle conditioning parameters and disk lowers nanoscale surface roughness and improves roughness uniformity across the wafer. A minimum material removal is required to reach the lowest roughness, after which Rq remains stable and independent of additional removal. This behavior is observed over four different ISDP film materials, regardless of the film thickness or post-deposition annealing. Hydrophobic direct bonding of a polished ISDP wafer to a monocrystalline silicon one yielded defect free interface and high bond strength, demonstrating the potential of the ISDP CMP process to produce surfaces compatible with demanding wafer level packaging requirements.

  https://doi.org/10.1149/2162-8777/ae72cd
• Erratum—ZnO and Simonkolleite Nanocomposite Synthesis via Green Chemistry Using Hibiscus Flower Extract [ECS J. Solid State Sci. Technol., 10, 123016 (2021)]

  Aida 

  View accepted manuscript, Erratum—ZnO and Simonkolleite Nanocomposite Synthesis via Green Chemistry Using Hibiscus Flower Extract [ECS J. Solid State Sci. Technol., 10, 123016 (2021)]PDF, Erratum—ZnO and Simonkolleite Nanocomposite Synthesis via Green Chemistry Using Hibiscus Flower Extract [ECS J. Solid State Sci. Technol., 10, 123016 (2021)]Open abstract

  This paper was withdrawn by IOP Publishing on 3 June 2024. The funding information in the Acknowledgments was corrected as a post-publication change direct to the published article rather than as this erratum.

  https://doi.org/10.1149/2162-8777/ac6f21

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• The following article is Open access
  Electron Beam Irradiation-Induced Transport and Recombination in P-type Diamond Diodes

  Gabriel P Marciaga et al 2026 ECS J. Solid State Sci. Technol. 15 075004

  View article, Electron Beam Irradiation-Induced Transport and Recombination in P-type Diamond DiodesPDF, Electron Beam Irradiation-Induced Transport and Recombination in P-type Diamond DiodesOpen abstract

  This study investigates minority carrier diffusion length (L) and defect-mediated recombination phenomena in boron-doped p-type diamond epitaxial layers. Utilizing temperature-dependent electron beam-induced current (EBIC) and cathodoluminescence (CL), the influence of temperature and sustained electron beam irradiation was characterized. The diamond sample demonstrates a pronounced thermal enhancement to the minority carrier diffusion length. This temperature enhancement for L has an activation energy of 177 meV. Furthermore, sustained electron injection induces a near-linear elongation of the diffusion length through passivation of deep-level defects. From the EBIC injection data, an activation energy of 151 meV was extracted from fitting. Temperature-resolved CL reveals the quenching of the characteristic A-band emission at 100 °C. Additionally, a thermal activation energy of 112 meV was extracted via a decay fit of the temperature dependent CL intensity data. While sustained electron beam irradiation reveals dose-dependent quenching of the A-band emission with thermally activated decay rates. This yields activation energies of 110 meV and 11 meV associated with distinct defect generation mechanisms at high and low temperatures, respectively. This provides a complementary assessment of the defect landscape governing minority carrier lifetimes in these boron-doped diamond diodes.

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  https://doi.org/10.1149/2162-8777/ae87cd
• The following article is Open access
  Impact of Channel Width on Electrical Characteristics for Inversion Mode N-Channel TFT on Polycrystalline Ge by Solid Phase Crystallization

  Linyu Huang et al 2026 ECS J. Solid State Sci. Technol. 15 064006

  View article, Impact of Channel Width on Electrical Characteristics for Inversion Mode N-Channel TFT on Polycrystalline Ge by Solid Phase CrystallizationPDF, Impact of Channel Width on Electrical Characteristics for Inversion Mode N-Channel TFT on Polycrystalline Ge by Solid Phase CrystallizationOpen abstract

  We have successfully synthesized high-quality polycrystalline (poly-) Ge thin films using an advanced solid-phase crystallization (SPC) technique and fabricated inversion-mode n-channel thin-film transistors (TFTs) on a glass substrate. However, its electrical performance still had room for improvement. Although the effect of channel geometry on device performance in poly-Si TFTs has been widely studied, similar consideration for poly-Ge TFTs has not been reported. In this study, we examined the effect of channel width on TFT performance metrics, including subthreshold swing, ON/OFF ratio, and threshold voltage. By changing the channel shape by reducing the channel width, the ON/OFF ratio of n-channel poly-Ge TFTs was significantly improved, and the behavior of other electrical properties is similar to that of poly-Si TFTs. Additionally, by changing the channel width of poly-Ge TFT, we determined the mobility of the grain boundaries in parallel to current flow within poly-Ge. The trend of estimated grain boundary’s mobility relative to the whole poly-Ge film mobility is similar to that of poly-Si, as estimated from complex simulation. This method can evaluate the conductive properties of grain boundaries in polycrystalline semiconductors and can be applied to polycrystalline semiconductors prepared using various methods.

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  https://doi.org/10.1149/2162-8777/ae79a7
• The following article is Open access
  Characteristics of β-Ga₂O₃/Al₂O₃/Pt Capacitors with a Ga₂O₃ Surface Modified Using the Dummy-SiO₂ Process

  Toshihide Nabatame et al 2026 ECS J. Solid State Sci. Technol. 15 064005

  View article, Characteristics of β-Ga2O3/Al2O3/Pt Capacitors with a Ga2O3 Surface Modified Using the Dummy-SiO2 ProcessPDF, Characteristics of β-Ga2O3/Al2O3/Pt Capacitors with a Ga2O3 Surface Modified Using the Dummy-SiO2 ProcessOpen abstract

  The characteristics of β-Ga₂O₃/Al₂O₃/Pt capacitors fabricated via the dummy-SiO₂ (d-SiO₂) process at 800 °C under O₂ (D-O₂), N₂ (D-N₂), and 3% H₂ (D-H₂) atmospheres were investigated. The surface of Ga₂O₃ after the d-SiO₂ process was as smooth as that after the sulfuric acid-hydrogen peroxide mixture treatment (Control). The flatband voltage (V_fb) hysteresis decreased as follows: Control (0.76 V) > D-H₂ (0.56 V) > D-N₂ (0.43 V) > D-O₂ (0.37 V). The interface state density of the D-O₂ capacitor was significantly reduced to 6 × 10¹¹ cm⁻²eV⁻¹ at −0.4 eV from conduction band. The V_fb shift caused by the electron traps according to the near-interface trap model under positive bias stress substantially improved for the capacitors fabricated by the d-SiO₂ process. The poor characteristics of the Control capacitor are due to the presence of the unstable layer on the Ga₂O₃ surface. The improved electrical characteristic of the d-SiO₂ capacitors is due to the modified Ga₂O₃ surface, which eliminated the unstable Ga₂O₃ layer. This is the result of hydrogen contained within the dummy SiO₂ layer supporting the removal of Ga₂O₃. The difference in the decomposition reaction of Ga₂O₃ due to the atmosphere gas of the d-SiO₂ process leads to differences in electrical properties.

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  https://doi.org/10.1149/2162-8777/ae7ac0
• The following article is Open access
  Investigation of Electrochemical Transport, Gate Leakage, and Transconductance Behavior in PEDOT:PSS Organic Electrochemical Transistors

  Vinay Budhraja et al 2026 ECS J. Solid State Sci. Technol. 15 067001

  View article, Investigation of Electrochemical Transport, Gate Leakage, and Transconductance Behavior in PEDOT:PSS Organic Electrochemical TransistorsPDF, Investigation of Electrochemical Transport, Gate Leakage, and Transconductance Behavior in PEDOT:PSS Organic Electrochemical TransistorsOpen abstract

  Organic Electrochemical Transistors (OECTs) are promising candidates for low-voltage bioelectronic systems due to their high transconductance, mixed ionic–electronic transport, and compatibility with flexible substrates. In this work, we investigate the electrochemical transport, gate leakage, and transconductance behavior of screen-printed PEDOT:PSS OECTs, with emphasis on the relationship between ionic coupling and output characteristics. Key electrical and electrochemical parameters—including drain current modulation, transconductance evolution, gate current behavior, and capacitance–voltage response—were systematically analyzed to elucidate the mechanisms governing device operation. The results reveal clear trade-offs between parasitic resistance, volumetric electrochemical capacitance, and effective gate control, which in turn influence signal integrity and amplification efficiency. Devices exhibiting reduced parasitic effects demonstrated lower gate leakage, improved signal-to-noise ratio, and more stable transconductance, whereas devices with stronger ionic coupling showed enhanced drain current at the expense of nonlinearity in the saturation regime. High-frequency C–V measurements and gate-current modeling further confirm distinct electrochemical dynamics driven by modulation of mixed conduction pathways. These insights provide a deeper understanding of OECT operation and offer practical guidelines for optimizing device architecture in solid-state and flexible bioelectronic applications.

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  https://doi.org/10.1149/2162-8777/ae7642
• The following article is Open access
  Impact of Face-to-Face Annealing on the Structural and Optical Stability of Sputtered Al_0.70Sc_0.30N Thin Films

  Sihang Hui et al 2026 ECS J. Solid State Sci. Technol. 15 064002

  View article, Impact of Face-to-Face Annealing on the Structural and Optical Stability of Sputtered Al0.70Sc0.30N Thin FilmsPDF, Impact of Face-to-Face Annealing on the Structural and Optical Stability of Sputtered Al0.70Sc0.30N Thin FilmsOpen abstract

  Reactive sputter deposition of Al_1−xSc_xN has shown great promise in the fabrication of next generation piezoelectric, ferroelectric, and optoelectronic applications. Due to the nature of sputtering, post-deposition, high temperature thermal processing is often used to improve the film crystalline quality and subsequently improve the overall device performance. However, a complete analysis on the thermal stability of high Sc content Al_1−xSc_xN remains as a gap that needs to be filled. In this work, reactive sputtered Al_0.70Sc_0.30N was annealed using a face-to-face configuration at temperatures between 1100 °C and 1300 °C, and for durations between 60 and 180 min to study the thermal impact on structural and optical properties. Annealing at 1100 °C for 60 mins under this configuration improved the thin film crystalline quality while maintaining phase purity and structural stability. Annealing at higher temperatures and durations led to ScN segregation, as well as Sc₂O₃ formation at the highest temperature regime. Optically, it was found that annealing can eliminate vacancy-oxygen complex defects and improve transmission in the deposited thin film.

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  https://doi.org/10.1149/2162-8777/ae6a6b
• The following article is Open access
  Synergistic Electrochemical Performance of CoFe₂O₄/Polypyrrole Composite Electrodes for Supercapacitor Applications

  Israa A. Najem et al 2026 ECS J. Solid State Sci. Technol. 15 061001

  View article, Synergistic Electrochemical Performance of CoFe2O4/Polypyrrole Composite Electrodes for Supercapacitor ApplicationsPDF, Synergistic Electrochemical Performance of CoFe2O4/Polypyrrole Composite Electrodes for Supercapacitor ApplicationsOpen abstract

  Hybrid electrode materials combining transition metal oxides and conductive polymers have attracted significant attention for supercapacitor applications. In this study, cobalt ferrite nanoparticles were synthesized via sol-gel method, and polypyrrole conductive polymer was prepared by chemical oxidative polymerization method. Composite electrodes were fabricated with different CoFe₂O₄/PPy rations and evaluated in 6 M KOH electrolyte. electrochemical analyses revealed stable operation within potential window 0 f 0–1.4 V and a hybrid charge storage mechanism combining electric double-layer capacitance and pseudocapacitance. Among the investigated samples, the CF6P2 electrode exhibited the best performance, delivering a specific capacitance of 296 mF cm⁻² (161 F g⁻¹) at 1 mV s⁻¹, along with an energy density of 50.35 Wh kg⁻¹. In addition, it demonstrated good cycling stability with 95% capacitance retention after 5000 cycles. The enhanced performance is attributed to the synergistic interaction between CoFe₂O₄ and PPy, which improves electrical conductivity and redox activity.

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  Highlights

  • The optimized CF6P2 electrode delivered 161 F g⁻¹ at 1 mV s⁻¹.

  • A high energy density of 50.35 Wh g⁻¹ was achieved for the CF6P2 electrode.

  • The electrode maintained 95% capacitance retention after 5000 cycles.

  • Synergistic interaction between CoFe₂O₄ and PPy enhanced charge storage performance.

  https://doi.org/10.1149/2162-8777/ae7543
• The following article is Open access
  Wet Etching Studies on CuGaO₂ and CuCrO₂ Thin Films

  Akash Hari Bharath et al 2026 ECS J. Solid State Sci. Technol. 15 063003

  View article, Wet Etching Studies on CuGaO2 and CuCrO2 Thin FilmsPDF, Wet Etching Studies on CuGaO2 and CuCrO2 Thin FilmsOpen abstract

  Wet etching of delafossite CuGaO₂ and CuCrO₂ thin films was investigated for the first time. CuGaO₂ films were exposed to concentrated HCl, nitric acid, and aluminum etchant at varying temperatures, with etch rates dependent on temperature. Concentrated HCl produced the highest etch rates. CuCrO₂ films were etched using an HCl–HNO₃ mixture at 40 °C–60 °C and chromium-based etchants at dilutions of 1:5 to 1:10. The fastest etching was observed in the 1:5 dilution, and slower rates were achieved through higher dilutions or lower temperatures. Optical microscopy confirmed well-defined patterns, achieving feature sizes as small as 19 μm. Preliminary Arrhenius analysis indicated thermally activated etching behavior, highlighting the strong influence of etchant chemistry on the etching mechanism.

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  https://doi.org/10.1149/2162-8777/ae7544
• The following article is Open access
  Charge-Trapping in Al₂O₃/AlO_x/SiO₂ Gate Stacks Prepared by Multi-Step Anodic Oxidation(ANO) for 4H-SiC Memory

  Yao Cheng Yang and Jenn-Gwo Hwu 2026 ECS J. Solid State Sci. Technol. 15 063002

  View article, Charge-Trapping in Al2O3/AlOx/SiO2 Gate Stacks Prepared by Multi-Step Anodic Oxidation(ANO) for 4H-SiC MemoryPDF, Charge-Trapping in Al2O3/AlOx/SiO2 Gate Stacks Prepared by Multi-Step Anodic Oxidation(ANO) for 4H-SiC MemoryOpen abstract

  In this work, a novel stoichiometry engineering approach using multi-step anodic oxidation (ANO) is proposed to fabricate a high-performance charge-trapping memory (CTM) device on an n-type 4H-SiC substrate. By precisely modulating the anodization process at room temperature, a functional gate stack comprising a sub-stoichiometric AlO_x charge trapping layer and a fully oxidized Al₂O₃ blocking layer was successfully formed. Material characterizations, including transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX), confirmed the distinct oxygen-deficient nature of the trap-rich AlO_x layer and the stoichiometric perfection of the Al₂O₃ barrier. Electrically, the fabricated Al/Al₂O₃/AlO_x/SiO₂/4H-SiC device exhibits a massive clockwise capacitance-voltage (C-V) hysteresis and an exceptionally low gate leakage current (below 10⁻¹⁰ A), verifying the efficacy of both the engineered defect states and the blocking mechanism. A significant normalized capacitance window (${\rm{\Delta }}{C}^{{\prime} }$) of 3.30 was achieved and stably maintained over 100 continuous program and erase cycles. The effective charge density stored in the device is around ΔN_eff = 2.48 × 10¹² cm⁻². The underlying charge trapping and de-trapping mechanisms are comprehensively elucidated using energy band models. This study demonstrates a highly promising, cost-effective, and ALD-free method for integrating reliable non-volatile memory on SiC platforms.

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  https://doi.org/10.1149/2162-8777/ae73f1
• The following article is Open access
  Stability Study of >13.5 kV Field Plated NiO/β-Ga₂O₃ Heterojunction Rectifiers Fabricated on 4-Inch Wafers

  Hsiao-Hsuan Wan et al 2026 ECS J. Solid State Sci. Technol. 15 065001

  View article, Stability Study of >13.5 kV Field Plated NiO/β-Ga2O3 Heterojunction Rectifiers Fabricated on 4-Inch WafersPDF, Stability Study of >13.5 kV Field Plated NiO/β-Ga2O3 Heterojunction Rectifiers Fabricated on 4-Inch WafersOpen abstract

  100 μm diameter vertical NiO/β-Ga₂O₃ heterojunction diodes with dielectric-assisted field-plate edge termination were fabricated on a 4-inch β-Ga₂O₃ wafer with ∼10–14 μm thick Si-doped 8.5 × 10¹⁵ cm⁻³ drift layers demonstrating breakdown voltages (V_B) exceeding 13.5 kV, limited by the measurement equipment, on-voltage (V_ON) of ∼2.2 V and on-state resistance R_ON of 5.5 mΩ·cm². The average critical breakdown field in heterojunctions was 9.6–13.5 MV cm⁻¹, within the reported theoretical value range from 8–15 MV cm⁻¹ for β-Ga₂O₃. The associated maximum power figure-of-merit, V_B²/R_ON of >33.1 GW cm⁻² was achieved. Scanning transmission electron microscopy (STEM) reveals a polycrystalline NiO layer with multiple crystallographic orientations and a well-defined device stack. Forward current–voltage measurements performed 10 days and 150 days after NiO deposition show stable turn-on behavior with only minor changes in low-bias current. Cross-sectional STEM and energy-dispersive X-ray spectroscopy (EDS) analysis reveal localized oxygen enrichment near the outer edge (∼500 nm) of the Ni contact on NiO, likely associated with fabrication-related oxidation, while the NiO/β-Ga₂O₃ heterojunction remains intact. These results demonstrate stable ultra-high-voltage operation of NiO/β-Ga₂O₃ heterojunction rectifiers fabricated on wafer-scale substrates, highlighting their potential for next-generation extreme-voltage power electronics.

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  https://doi.org/10.1149/2162-8777/ae72ce
• The following article is Open access
  Chemical Mechanical Polishing of In-Situ-Doped Polysilicon for MEMS Applications

  Vincent Pares et al 2026 ECS J. Solid State Sci. Technol.

  View article, Chemical Mechanical Polishing of In-Situ-Doped Polysilicon for MEMS ApplicationsPDF, Chemical Mechanical Polishing of In-Situ-Doped Polysilicon for MEMS ApplicationsOpen abstract

  This work presents a 200 mm wafer-scale single step industrial Chemical Mechanical Polishing (CMP) process to polish in-situ doped polysilicon using a commercial silica-based slurry. By tuning CMP operating conditions and pad conditioning, the surface roughness is reduced uniformly across the wafer down to Rq = 0.22 nm. Roughness reduction, is primarily driven by surface chemical reactions. Using gentle conditioning parameters and disk lowers nanoscale surface roughness and improves roughness uniformity across the wafer. A minimum material removal is required to reach the lowest roughness, after which Rq remains stable and independent of additional removal. This behavior is observed over four different ISDP film materials, regardless of the film thickness or post-deposition annealing. Hydrophobic direct bonding of a polished ISDP wafer to a monocrystalline silicon one yielded defect free interface and high bond strength, demonstrating the potential of the ISDP CMP process to produce surfaces compatible with demanding wafer level packaging requirements.

  https://doi.org/10.1149/2162-8777/ae72cd

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• The following article is Open access
  Review—Ionizing Radiation Damage Effects on GaN Devices

  S. J. Pearton et al 2016 ECS J. Solid State Sci. Technol. 5 Q35

  View article, Review—Ionizing Radiation Damage Effects on GaN DevicesPDF, Review—Ionizing Radiation Damage Effects on GaN DevicesOpen abstract

  Gallium Nitride based high electron mobility transistors (HEMTs) are attractive for use in high power and high frequency applications, with higher breakdown voltages and two dimensional electron gas (2DEG) density compared to their GaAs counterparts. Specific applications for nitride HEMTs include air, land and satellite based communications and phased array radar. Highly efficient GaN-based blue light emitting diodes (LEDs) employ AlGaN and InGaN alloys with different compositions integrated into heterojunctions and quantum wells. The realization of these blue LEDs has led to white light sources, in which a blue LED is used to excite a phosphor material; light is then emitted in the yellow spectral range, which, combined with the blue light, appears as white. Alternatively, multiple LEDs of red, green and blue can be used together. Both of these technologies are used in high-efficiency white electroluminescent light sources. These light sources are efficient and long-lived and are therefore replacing incandescent and fluorescent lamps for general lighting purposes. Since lighting represents 20–30% of electrical energy consumption, and because GaN white light LEDs require ten times less energy than ordinary light bulbs, the use of efficient blue LEDs leads to significant energy savings. GaN-based devices are more radiation hard than their Si and GaAs counterparts due to the high bond strength in III-nitride materials. The response of GaN to radiation damage is a function of radiation type, dose and energy, as well as the carrier density, impurity content and dislocation density in the GaN. The latter can act as sinks for created defects and parameters such as the carrier removal rate due to trapping of carriers into radiation-induced defects depends on the crystal growth method used to grow the GaN layers. The growth method has a clear effect on radiation response beyond the carrier type and radiation source. We review data on the radiation resistance of AlGaN/GaN and InAlN/GaN HEMTs and GaN–based LEDs to different types of ionizing radiation, and discuss ion stopping mechanisms. The primary energy levels introduced by different forms of radiation, carrier removal rates and role of existing defects in GaN are discussed. The carrier removal rates are a function of initial carrier concentration and dose but not of dose rate or hydrogen concentration in the nitride material grown by Metal Organic Chemical Vapor Deposition. Proton and electron irradiation damage in HEMTs creates positive threshold voltage shifts due to a decrease in the two dimensional electron gas concentration resulting from electron trapping at defect sites, as well as a decrease in carrier mobility and degradation of drain current and transconductance. State-of-art simulators now provide accurate predictions for the observed changes in radiation-damaged HEMT performance. Neutron irradiation creates more extended damage regions and at high doses leads to Fermi level pinning while ⁶⁰Co γ-ray irradiation leads to much smaller changes in HEMT drain current relative to the other forms of radiation. In InGaN/GaN blue LEDs irradiated with protons at fluences near 10¹⁴ cm⁻² or electrons at fluences near 10¹⁶ cm⁻², both current-voltage and light output-current characteristics are degraded with increasing proton dose. The optical performance of the LEDs is more sensitive to the proton or electron irradiation than that of the corresponding electrical performances.

  https://doi.org/10.1149/2.0251602jss
• The following article is Open access
  Perspective—Opportunities and Future Directions for Ga₂O₃

  Michael A. Mastro et al 2017 ECS J. Solid State Sci. Technol. 6 P356

  View article, Perspective—Opportunities and Future Directions for Ga2O3PDF, Perspective—Opportunities and Future Directions for Ga2O3Open abstract

  The β-polytype of Ga₂O₃ has a bandgap of ∼4.8 eV, can be grown in bulk form from melt sources, has a high breakdown field of ∼8 MV.cm⁻¹ and is promising for power electronics and solar blind UV detectors, as well as extreme environment electronics (high temperature, high radiation, and high voltage (low power) switching. High quality bulk Ga₂O₃ is now commercially available from several sources and n-type epi structures are also coming onto the market. There are also significant efforts worldwide to grow more complex epi structures, including β-(Al_xGa_1x)₂O₃/Ga₂O₃ and β-(In_xGa_1−x)₂O₃/Ga₂O₃ heterostructures, and thus this materials system is poised to make rapid advances in devices. To fully exploit these advantages, advances in bulk and epitaxial crystal growth, device design and processing are needed. This article provides some perspectives on these needs.

  https://doi.org/10.1149/2.0031707jss
• The following article is Open access
  Review—Influence of Processing Parameters to Control Morphology and Optical Properties of Sol-Gel Synthesized ZnO Nanoparticles

  Sandeep Arya et al 2021 ECS J. Solid State Sci. Technol. 10 023002

  View article, Review—Influence of Processing Parameters to Control Morphology and Optical Properties of Sol-Gel Synthesized ZnO NanoparticlesPDF, Review—Influence of Processing Parameters to Control Morphology and Optical Properties of Sol-Gel Synthesized ZnO NanoparticlesOpen abstract

  ZnO has several potential applications into its credit. This review article focuses on the influence of processing parameters involved during the synthesis of ZnO nanoparticles by sol-gel method. During the sol-gel synthesis technique, the processing parameters/experimental conditions can affect the properties of the synthesized material. Processing parameters are the operating conditions that are to be kept under consideration during the synthesis process of nanoparticles so that various properties exhibited by the resulting nanoparticles can be tailored according to the desired applications. Effect of parameters like pH of the sol, additives used (like capping agent, surfactant), the effect of annealing temperature and calcination on the morphology and the optical properties of ZnO nanoparticles prepared via sol-gel technique is analyzed in this study. In this study, we tried to brief the experimental investigations done by various researchers to analyze the influence of processing parameters on ZnO nanoparticles. This study will provide a platform to understand and establish a correlation between the experimental conditions and properties of ZnO nanoparticles prepared through sol-gel route which will be helpful in meeting the desired needs in various application areas.

  https://doi.org/10.1149/2162-8777/abe095
• The following article is Open access
  Review—Photoluminescence Properties of Cr³⁺-Activated Oxide Phosphors

  Sadao Adachi 2021 ECS J. Solid State Sci. Technol. 10 026001

  View article, Review—Photoluminescence Properties of Cr3+-Activated Oxide PhosphorsPDF, Review—Photoluminescence Properties of Cr3+-Activated Oxide PhosphorsOpen abstract

  The Cr³⁺-activated phosphor properties are discussed in detail from an aspect of spectroscopic point of view. The host materials considered here are a various kind of oxide compounds. The photoluminescence (PL) and PL excitation spectra of the Cr³⁺-activated oxide phosphors are analyzed based on Franck−Condon analysis within the configurational-coordinate model. A new method is proposed for obtaining reliable crystal-field (Dq) and Racah parameters (B and C) based on a general ligand field theory with paying an attention to difficulty in the exact estimation of such important ligand field parameters. The intra-d-shell Cr³⁺ states, such as ²E_g (²G), ⁴T_2g (⁴F), and ⁴T_1g (⁴F), in various oxide hosts are determined and plotted against Dq in the Tanabe−Sugano energy-level diagram. The results obtained are summarized in graphical and tabular forms. A comparative discussion of Cr³⁺ ion as an efficient activator in oxide and fluoride hosts is also given. The present analysis method can be used to predict an energy of Cr³⁺ emission and/or to check a validity of the Racah parameter values for a variety of Cr³⁺-activated phosphors and related optical and optoelectronic device applications.

  https://doi.org/10.1149/2162-8777/abdc01
• Tailoring Structural, Optical, and Dielectric Properties of PVC/PMMA/PS/ZnO Nanocomposites for Capacitive Energy Storage Applications

  A. A. Al-Muntaser et al 2025 ECS J. Solid State Sci. Technol. 14 033001

  View article, Tailoring Structural, Optical, and Dielectric Properties of PVC/PMMA/PS/ZnO Nanocomposites for Capacitive Energy Storage ApplicationsPDF, Tailoring Structural, Optical, and Dielectric Properties of PVC/PMMA/PS/ZnO Nanocomposites for Capacitive Energy Storage ApplicationsOpen abstract

  Using a conventional casting method, flexible polymeric film nanocomposites composed of PMMA (polymethyl methacrylate), PS (polystyrene), PVC (polyvinyl chloride) and ZnO nanoparticles were synthesized. Fourier transform infrared (FTIR) spectroscopy identified distinct peaks corresponding to vibrational groups in the prepared samples. Upon doping the PVC/PMMA/PS blend with varying concentrations of ZnO NPs (2.5–10 wt%), most absorption intensities tend to diminish progressively as the ZnO contents have been increased to 5 wt%. Changes in FTIR vibrational bands indicated interactions between the PVC/PMMA/PS/ZnO nanocomposite constituents. The XRD patterns of the ZnO NPs-based composites have exhibited the same peaks of the pure blend; however, there is a notable increase in broadness and a significant reduction in intensity as the weight percentage of ZnO NPs rises from 2.5 to 10. This observation indicates the development of interactions between the polymer and nanoparticles. The redshift seen in the absorption edge of the samples filled with ZnO provided strong evidence that charge transfer complexes had formed inside the polymeric matrix. The indirect and direct energy gaps for allowable transitions decreased with increasing ZnO NP concentrations, ranging from 3.88 eV and 4.87 eV in the pure blend to 3.31 eV and 4.67 eV, respectively. The σ_AC value at 100 Hz was 8.41 × 10⁻¹³ S·cm⁻¹ and increased with frequency, reaching 5.12 × 10⁻⁹ S·cm⁻¹ at 10⁶ Hz. Also, a modest improvement in σ_AC values is observed with the increase of ZnO NPs loading. The increase in conductivity can be ascribed to the improved amorphous nature of the synthesized nanocomposite facilitated by the incorporation of ZnO NPs. Dielectric studies showed that the best improvement was attained for the PVC/PMMA/PS/5 wt% of ZnO nanocomposite sample. Further, its imaginary part (ε″) exhibited a constructive decrease in its value with the increase in the ZnO loadings. These findings recommend these nanocomposites for potential applications in optoelectronics and energy storage devices.

  https://doi.org/10.1149/2162-8777/adb992
• Study of Optical, Thermal, Electrical, and Impedance Properties of Li₄Ti₅O₁₂-Based PEO/SA Biopolymer Blend Electrolytes for Lithium-Ion Batteries

  F. E. Hanash et al 2025 ECS J. Solid State Sci. Technol. 14 023011

  View article, Study of Optical, Thermal, Electrical, and Impedance Properties of Li4Ti5O12-Based PEO/SA Biopolymer Blend Electrolytes for Lithium-Ion BatteriesPDF, Study of Optical, Thermal, Electrical, and Impedance Properties of Li4Ti5O12-Based PEO/SA Biopolymer Blend Electrolytes for Lithium-Ion BatteriesOpen abstract

  Nanocomposites composed of polyethylene oxide (PEO) and sodium alginate (SA), containing varying contents of lithium titanium oxide nanoparticles (Li₄Ti₅O₁₂NPs), were synthesized by solution casting technique. Li₄Ti₅O₁₂ was incorporated into PEO/SA blend and is a valuable biopolymer for its biocompatibility, solubility and eco-friendliness. Structural analysis via X-ray diffraction spectroscopy revealed a decrease in the crystallinity of PEO/SA matrix with increasing nanoparticle content. Complementary Fourier transform infrared analysis verified the presence of strong molecular interactions between Li₄Ti₅O₁₂ and the blend chains. Scanning electron microscopy verified a uniform dispersion of Li₄Ti₅O₁₂ within PEO/SA blend, contributing to the improved properties of the electrolytes, while optical analysis showed a decrease in the bandgap energy, indicating enhanced light absorption and improved suitability for applications in nanodielectric devices. The thermal stability of PEO/SA/Li₄Ti₅O₁₂ electrolyte samples was improved as shown by thermogravimetric analysis. Furthermore, a significant improvement in the ionic conductivity of the filled samples was observed, attributed to the reduced bulk resistance and improved charge transport pathways. Dielectric studies further showed improved dielectric permittivity and reduced dielectric losses for filled samples, enhancing the material’s charge storage capability. These findings highlight the potential of PEO/SA/Li₄Ti₅O₁₂ biopolymer electrolytes for advanced applications in nanodielectric devices and lithium-ions batteries.

  https://doi.org/10.1149/2162-8777/adb78e
• The following article is Open access
  Investigation of InAlN Layers Surface Reactivity after Thermal Annealings: A Complete XPS Study for HEMT

  Y. Bourlier et al 2018 ECS J. Solid State Sci. Technol. 7 P329

  View article, Investigation of InAlN Layers Surface Reactivity after Thermal Annealings: A Complete XPS Study for HEMTPDF, Investigation of InAlN Layers Surface Reactivity after Thermal Annealings: A Complete XPS Study for HEMTOpen abstract

  The surface chemistry of InAlN ultra-thin layers, having undergone an oxidation procedure usually running through the HEMT fabrication process (850°C, O₂ and O₂+Ar) is studied by XPS. The suitability of XPS analysis to operate as a retro-engineering tool for added value microelectronic devices fabrication is shown. A precise examination of the Al2p, In3d_5/2, N1s, and O1s peaks directly informs about spatial and atomic arrangement. The formation of a covering 3 nm surface oxide is evidenced after O₂ annealing. Once annealed, two specific additional N1s contributions are shown, at higher (404.0 eV) and lower binding energies (397.4 eV) compared to the InAlN matrix one (396.5 eV). To our knowledge, such fingerprint is rather unusual for ternary III-V materials. It reveals the formation of a nitrogen deficient interlayer, situated between the oxide overlayer and the undisturbed matrix, and the presence of interstitial N₂ molecules trapped at the interface. After Ar annealing, both oxide and interface layers are partially reorganized. InAlN reactivity toward higher annealing temperature (950°C) and its stability over time is finally discussed. N₂ molecules are unstable and progressively eliminated in time although nitrogen deficient interlayer still remains. Thermal treatments below 850°C are recommended to preserve the barrier chemical integrity.

  https://doi.org/10.1149/2.0181806jss
• The following article is Open access
  Editors' Choice—Review—Theory and Characterization of Doping and Defects in β-Ga₂O₃

  Marko J. Tadjer et al 2019 ECS J. Solid State Sci. Technol. 8 Q3187

  View article, Editors' Choice—Review—Theory and Characterization of Doping and Defects in β-Ga2O3PDF, Editors' Choice—Review—Theory and Characterization of Doping and Defects in β-Ga2O3Open abstract

  Gallium oxide (β-Ga₂O₃) is an emerging semiconductor with relevant properties for power electronics, solar-blind photodetectors, and some sensor applications due to its ultra-wide bandgap and developing technology base for high quality, melt-based substrate growth and thick, low-doped homoepitaxial layers. Of critical importance for the commercialization of this potentially important material is understanding of doping mechanisms in the monoclinic lattice, where two types of Ga sites and three types of O sites have been identified. A critical literature review of doping and defects of the monoclinic β-phase of gallium oxide is provided in this work. Theoretical fundamentals of both donor and acceptor doping in Ga₂O₃ are reviewed. Advances in doping of epitaxial Ga₂O₃ with a focus on molecular beam epitaxy and ion implantation are critically examined. As doping is fundamentally related to defects, particularly in this material, a review of defect characterization by optical and electrical spectroscopic methods is provided as well. P-type doping, one of the fundamental challenges for Ga₂O₃, is discussed in terms of first-principles calculations and ion implantation of known acceptors such as Mg and N.

  https://doi.org/10.1149/2.0341907jss
• Scaling-Up of Bulk β-Ga₂O₃ Single Crystals by the Czochralski Method

  Zbigniew Galazka et al 2017 ECS J. Solid State Sci. Technol. 6 Q3007

  View article, Scaling-Up of Bulk β-Ga2O3 Single Crystals by the Czochralski MethodPDF, Scaling-Up of Bulk β-Ga2O3 Single Crystals by the Czochralski MethodOpen abstract

  We present a new approach for scaling-up the growth of β-Ga₂O₃ single crystals grown from the melt by the Czochralski method, which has also a direct application to other melt-growth techniques involving a noble metal crucible. Experimental and theoretical results point to melt thermodynamics as the crucial factor in increasing the volume of a growing crystal. In particular, the formation of metallic gallium in the liquid phase in large melt volumes causes problems with crystal growth and eutectic or intermetallic phase formation with the noble metal crucible. The larger crystals to be grown the higher oxygen concentration is required. The minimum oxygen concentration ranges from about 8 to 100 vol.% for 2 to 4 inch diameter cylindrical crystals, challenging the use of iridium crucibles in a combination with such high oxygen concentrations. A specific way of oxygen delivery to a growth furnace with the iridium crucible allows to minimize the formation of metallic gallium in the melt and thus obtaining large crystal volumes while decreasing the probability of the eutectic formation.

  https://doi.org/10.1149/2.0021702jss
• Review—Radiation Damage in Wide and Ultra-Wide Bandgap Semiconductors

  S. J. Pearton et al 2021 ECS J. Solid State Sci. Technol. 10 055008

  View article, Review—Radiation Damage in Wide and Ultra-Wide Bandgap SemiconductorsPDF, Review—Radiation Damage in Wide and Ultra-Wide Bandgap SemiconductorsOpen abstract

  The wide bandgap semiconductors SiC and GaN are already commercialized as power devices that are used in the automotive, wireless, and industrial power markets, but their adoption into space and avionic applications is hindered by their susceptibility to permanent degradation and catastrophic failure from heavy-ion exposure. Efforts to space-qualify these wide bandgap power devices have revealed that they are susceptible to damage from the high-energy, heavy-ion space radiation environment (galactic cosmic rays) that cannot be shielded. In space-simulated conditions, GaN and SiC transistors have shown failure susceptibility at ∼50% of their nominal rated voltage. Similarly, SiC transistors are susceptible to radiation damage-induced degradation or failure under heavy-ion single-event effects testing conditions, reducing their utility in the space galactic cosmic ray environment. In SiC-based Schottky diodes, catastrophic single-event burnout (SEB) and other single-event effects (SEE) have been observed at ∼40% of the rated operating voltage, as well as an unacceptable degradation in leakage current at ∼20% of the rated operating voltage. The ultra-wide bandgap semiconductors Ga₂O₃, diamond and BN are also being explored for their higher power and higher operating temperature capabilities in power electronics and for solar-blind UV detectors. Ga₂O₃ appears to be more resistant to displacement damage than GaN and SiC, as expected from a consideration of their average bond strengths. Diamond, a highly radiation-resistant material, is considered a nearly ideal material for radiation detection, particularly in high-energy physics applications. The response of diamond to radiation exposure depends strongly on the nature of the growth (natural vs chemical vapor deposition), but overall, diamond is radiation hard up to several MGy of photons and electrons, up to 10¹⁵ (neutrons and high energetic protons) cm⁻² and >10¹⁵ pions cm⁻². BN is also radiation-hard to high proton and neutron doses, but h-BN undergoes a transition from sp² to sp³ hybridization as a consequence of the neutron induced damage with formation of c-BN. Much more basic research is needed on the response of both the wide and ultra-wide bandgap semiconductors to radiation, especially single event effects.

  https://doi.org/10.1149/2162-8777/abfc23