ECS Journal of Solid State Science and Technology

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.

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.

Bound to complex perovskite systems, ferroelectric random access memory (FRAM) suffers from limited CMOS-compatibility and faces severe scaling issues in today's and future technology nodes. Nevertheless, compared to its current-driven non-volatile memory contenders, the field-driven FRAM excels in terms of low voltage operation and power consumption and therewith has managed to claim embedded as well as stand-alone niche markets. However, in order to overcome this restricted field of application, a material innovation is needed. With the ability to engineer ferroelectricity in HfO₂, a high-k dielectric well established in memory and logic devices, a new material choice for improved manufacturability and scalability of future 1T and 1T-1C ferroelectric memories has emerged. This paper reviews the recent progress in this emerging field and critically assesses its current and future potential. Suitable memory concepts as well as new applications will be proposed accordingly. Moreover, an empirical description of the ferroelectric stabilization in HfO₂ will be given, from which additional dopants as well as alternative stabilization mechanism for this phenomenon can be derived.

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.

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.

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.

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.

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.

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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This article provides an overview of the state-of-the-art chemistry and processing technologies for silicon nitride and silicon nitride-rich films, i.e., silicon nitride with C inclusion, both in hydrogenated (SiN_x:H and SiN_x:H(C)) and non-hydrogenated (SiN_x and SiN_x(C)) forms. The emphasis is on emerging trends and innovations in these SiN_x material system technologies, with focus on Si and N source chemistries and thin film growth processes, including their primary effects on resulting film properties. It also illustrates that SiN_x and its SiN_x(C) derivative are the focus of an ever-growing research and manufacturing interest and that their potential usages are expanding into new technological areas.

Low metal-semiconductor contact resistance can be realized via real ohmic contacts or low tunnel-barrier Schottky contacts. In gallium nitride (GaN)-based devices, alloying GaN and metals, such as Ti, Al and Au, is employed as a strategy for realizing metal-GaN ohmic contacts. In this study, ohmic-like contact is realized by thinning the tunnel barrier via the formation of a highly Si-doped n-GaN region. The sheet resistance (R_sh), which is linked to carrier density and contact resistivity, is influenced by the cap layers deployed for sacrificial layers of ion implantation and activation annealing. To evaluate contact resistivity using transfer length method (TLM) patterning, the silicon nitride (SiN) cap layer is selected for realizing low R_sh of n-GaN layer. At high doping concentrations and activation-annealing temperatures, the GaN and SiN layers react to form reaction products. Thereafter, the dose and temperature are set to 3.0 × 10¹⁵ cm⁻² and 1100 °C, respectively. Under these conditions, the estimated carrier density at the GaN surface is 3.9 × 10²⁰ cm⁻³, confirming the formation of the n⁺-GaN region. The subsequent measurements of the fabricated TLM pattern using Au-free Ti/Al electrodes confirm the realization of ohmic-like behavior at a low post-metallization-annealing temperature of 450 °C, yielding a low contact resistivity of 6.6 × 10⁻⁶ Ωcm².

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The Phy-X software facilitated the exploration of lead bismuth borate glasses’ radiation shielding performance when doped with different Gd₂O₃ content in the wide 0.015–15 MeV energy range. The effective atomic number (Z_eff) and LAC were progressively increased with greater BaO, PbO₂, and Gd₂O₃ content. The glasses’ Z_eff values had significant dependence on the radiation energy, since the Z_eff changed rapidly with increased energy and in the low energy range this change was very notable. The high density sample (coded as Gd3) had the lowest half-value layer (HVL), indicating this glass sample as possessing the maximum shielding effect. The prepared glasses’ HVL values were compared with additional glasses at 0.5 MeV, whereby the values of all the glass samples in this study were lower than the compared CaF₂-BaO-P₂O₅ and BaO-Li₂O-B₂O₃ glasses.

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The luminescence properties of the 3d³ (Mn⁴⁺, Cr³⁺)-ion-activated phosphors have been discussed in detail. All the phosphor materials activated by such 3d³ ions can be classified from the crystal-field (CF) strength-related parameter values of Dq/B into three groups: A (Dq/B > c_F), B (Dq/B ∼ c_F), and C (Dq/B < c_F), where c_F is the critical Dq/B value at which the zero-phonon line (ZPL) energy of the ²E_g-related transitions is the same as that of the ⁴T_2g-related ones [i.e., E(²E_g)_ZPL = E(⁴T_2g)_ZPL] on the Tanabe−Sugano (T − S) energy-level diagram. The photoluminescence (PL) and PL excitation spectra are analyzed based on the Franck−Condon analysis model with considering the electron−lattice vibration interaction (Huang−Rhys factor). The Racah and CF-related parameters of these phosphor groups are determined and found to be plotted very well on the T − S energy-level diagram. The temperature-dependent integrated PL intensities for the three phosphor groups of A, B, and C are also analyzed based on a common theoretical model for better understanding such scientifically interesting and technologically important subject.

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Developing persistent luminescence (PersL) materials that operate reliably at elevated temperatures is challenging due to rapid trap depopulation and thermal quenching of emission. Here, we demonstrate long-lasting PersL for several hours with stable multi-modal and multi-color emission at temperatures as high as 300 °C from Tb³⁺ in LaAlO₃ host system after being co-doped with Eu³⁺ and Yb³⁺ for the first time. These LaAlO₃:Tb³⁺,Eu³⁺,Yb³⁺ nanoparticles, synthesized via co-precipitation followed by a molten salt reaction, exhibit efficient downconversion, upconversion, PersL, optically stimulated luminescence (OSL), and thermally stimulated luminescence (TSL). TSL reveals four continuous trap levels, including a deep trap (∼290 °C) responsible for long-term charge storage and high-temperature stability. Notably, Tb³⁺ dopant acts not only as an emission center but also as an auxiliary trap for Eu³⁺ in the co-doped system. Density functional theory (DFT) calculations provide a unified trapping–de-trapping mechanism consistent with experimental results. These luminescent nanoparticles further exhibit strong radioluminescence with linear X-ray response, highlighting its potential as a scintillator, while its PersL further underscores its suitability for storage and imaging applications. These findings overcome the limitation of poor PersL in LaAlO₃ and position our LaAlO₃-based luminescent nanoparticles as desirable candidates for high-temperature optical data storage and anti-counterfeiting technologies.

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For core materials with fast response times and adjustable power and energy output for energy storage, we herein report the electrochemical performance and latent hydrogen evolution reaction of sheaf-like carbon nanotube (s-CNT) based material electrodes, aiming for further low-cost synthesis and environmentally friendly supercapacitor applications. XPS scanning spectra show C, O, and a few Mo elements with estimated contents of 82.3, 17.2, and 0.5 at%, respectively. The maximum capacitance of 1287 F g^‒1 is achieved in the s-CNT-based electrochemical double-layer capacitor (EDLC) due to slow ion diffusion in the s-CNT-based electrode during charging and discharging. The Bode phase angle at 80.1° of the s-CNT electrode is close to 90°, and the prepared s-CNT electrode illustrates ideal EDLC capacitance behavior. In addition, the s-CNT electrode, after 2000 subsequent CV and GCD cycles at a current density of 0.95 A g^‒1, retains specific capacitance of 96.8% and 80.55%, respectively. The s-CNT electrode exhibits reduced ionic resistance and facilitates ion transport through its conductive architecture, demonstrating its potential as a high-performance material for prospective EDLC supercapacitor applications.

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Highlights

• 12 ± 2 layers inside a single s-CNT

• Maximum capacitance of 1287 F g^‒1 was achieved in a concentrated 6 M KOH _(aq) medium

• Exhibits an energy density of 161 Wh kg^‒1 at a power density of 0.14 kW kg^‒1

• Specific capacitance retention is 96.8% and 80.55% of CV and GCD cycles, respectively

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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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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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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Resistive gas sensors are widely utilized to detect a variety of gases including poisonous, explosive, biomarker, and even non-toxic gases because of their exceptional performance. Zinc stannate (Zn₂SnO₄) is a ternary metal oxide with exceptional stability and distinctive electrical characteristics. In a variety of morphologies and along with other materials, it has been utilized to realize resistive gas sensors. Here, we thoroughly explain the gas sensing characteristics of Zn₂SnO₄ gas sensors in pristine, doped, and composite forms. Also, we have emphasized in sensing mechanism to further understand the gas sensing principle of Zn₂SnO₄ gas sensors.

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In chemical mechanical polishing (CMP), abrasives are the primary factors determining polishing performance. To achieve high-precision polishing results with a controlled material removal rate (MRR) and minimized surface defects, increasingly stringent demands are placed on abrasive characteristics, including particle size, hardness, morphology, and chemical stability. As a result, the research and development of modified abrasives have become critical for enhancing polishing performance. This paper systematically summarizes the progress of research in abrasive modification over recent years to improve polishing results, focusing on the mechanisms of action and polishing performance of CeO₂ and TiO₂ abrasives. It is concluded that modified CeO₂ abrasives (such as core–shell structured abrasives, rare Earth element-doped abrasives, and mixed abrasives) exhibit excellent polishing effects by improving their original physicochemical properties or integrating with the properties of other abrasives. Furthermore, in photocatalysis-assisted chemical mechanical polishing (PCMP), modified TiO₂ abrasives generally generate highly oxidizing hydroxyl radicals (·OH), which exhibit advantages for the processing difficulty of third-generation semiconductors SiC and GaN. Looking ahead, research on modified abrasives will remain a top priority. The continuous optimization of abrasive properties is expected to lead to a more efficient and environmentally friendly semiconductor manufacturing process.

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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.

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.

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.

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.

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.

Selective electroless-deposited (ELD) passivation layer bonding is an advanced process known by low process complexity and low cost, which can effectively reduce the bonding temperature. However, a pressing issue is that metal particles from the process tend to deposit on the dielectric layer, thereby compromising reliability. By optimizing the boric acid (H3BO3) concentration to 96 mM, we achieved highly selective ELD Co films on Cu/SiO2 surfaces, effectively suppressing Co adsorption and particle formation on SiO2 while maintaining the deposition rate on Cu. Mechanistic studies, including contact angle measurements and Density Functional Theory calculations, revealed that the enhanced selectivity originated from the dissociative adsorption of H3BO3 on SiO2. This process passivated the surface by saturating dangling oxygen bonds, thereby inhibiting Co adsorption. We successfully demonstrated the application of this selective deposition in bonding technology, achieving Co-passivated layer bonding at 250 °C. Remarkably, after formic acid treatment, the bonding samples exhibited specific contact resistance comparable to those achieved with physical vapor deposition Co, highlighting the potential of this low-cost wet process for advanced interconnect fabrication.

This paper employs metal-organic chemical vapor deposition to grow a stress relieved InGaN laser cell with an InGaN quantum structure on a sapphire substrate, achieving a photovoltaic conversion efficiency of 11.76%. Through testing and characterization of the optical properties of InGaN materials, it found that compared with conventional structures, the surface roughness of materials containing stress relief layer with InGaN quantum structures increased by 21.1%, and absorption rate increased by 63.98%. However, the full width at half maximum, dislocation density and relaxation degree of the active region decreased by 23.29%, 46.63%, and 54.04%, respectively. Meanwhile, compared to conventional laser cells, its conversion efficiency increased by 3.51 times under 450nm laser irradiation. Therefore, both the decrease in dislocation density and the improvement in absorption rate of the InGaN material with stress relief layer with InGaN quantum structures are the primary reasons for enhancing the device's conversion efficiency. In summary, this study provides reliable experimental support for the preparation of highly efficient InGaN laser cells.

To improve the lapping efficiency and process stability of quartz glass, this paper investigated the lapping mechanism of raised abrasive pads (RAP). Two types of fixed abrasive pads (FAP)—raised and flat—were fabricated via UV curing for comparative lapping experiments, through which their underlying mechanisms were explored in depth. And computational fluid dynamics (CFD) simulation software was used to simulate the machining process of the abrasive pad (AP), and the effect of the two structures on the flow rate of the abrasive fluid was comparatively analyzed. Experimental results revealed that the RAP achieved a material removal rate (MRR) of 1.91 μm/min, which is more than double the 0.95 μm/min MRR obtained with the flat abrasive pad. Furthermore, the CFD simulation shows that the flow velocity of the lapping fluid on the surface of the RAP (0.102 m/s) is greater than that of the flat AP (0.086 m/s). Compared with the flat AP, the raised structure on the surface of the RAP can effectively prevent the formation of liquid film, which greatly enhances the effect of the AP in discharging abrasive debris.

Based on the Non-Ionizing Energy Loss (NIEL) theory and the Boltzmann transport equation, this study systematically examines the damage behavior of InxGa1-xAs alloys under neutron irradiation, considering variations in layer thickness, indium mole fraction (x), and incident neutron energy. The findings reveal that in micron-scale thin targets, the NIEL values remain nearly composition-independent, whereas in thick targets, a pronounced attenuation of NIEL with depth is observed. The total number of Primary Knock-on Atoms (PKA) decreases noticeably with increasing neutron energy and indium content. For displaced atoms, in the low-energy region (<0.1 MeV), the damage primarily arises from elastic scattering, resulting in a relatively smaller number of displaced atoms. As neutron energy increases, inelastic scattering begins to play a significant role. In the high-energy region (>1 MeV), both scattering mechanisms act synergistically, with a single reaction capable of producing up to thousands of displaced atoms, leading to cascade damage. The non-ionizing energy deposition (Tdam) under thin-target conditions shows differences among alloys of varying compositions mainly in magnitude, while under thick-target conditions, it demonstrates an exponential decay trend with depth.

The ability to achieve high electrically active dopant concentration exceeding the solid solubility limit is critical for reducing specific contact resistivity (ρ_c) in advanced CMOS contacts. Oxidation-induced dopant segregation presents a promising pathway to enhance surface dopant concentration; however, success depends on attaining high activation while preserving a low‑defect interface. To achieve both enhanced dopant activation and reduced specific contact resistivity, this study investigates O₂ ambient spike annealing in Ti/n⁺-Si contacts, comparing its effectiveness with in-situ steam generation (ISSG) oxidation. We demonstrate that O₂ spike annealing yields a ρ_c of 1.17×10^-8 Ω·cm² —a 38.7% reduction relative to the N₂ ambient spike annealing reference and outperforming ISSG-treated samples. Notably, while ISSG yields a higher interfacial chemical phosphorus concentration, the O₂ spike annealed sample exhibits superior electrical characteristics, including lower sheet resistance and higher Hall carrier concentration. The improvement is attributed to the short-duration high-temperature dry oxidation process of O₂ spike annealing, which promotes effective phosphorus segregation into substitutional lattice sites while concurrently forming a low‑defect surface conducive to carrier tunneling. Our findings underscore that ρ_c is governed by both dopant activation concentration and interface quality, establishing O₂ ambient spike annealing as a simple, thermal-budget-efficient process for contact engineering.

The growing need for environmentally responsible, safe, and resource-efficient energy storage materials has driven interest in biodegradable polymer electrolytes. This work reports the design and evaluation of an eco-friendly solid polymer electrolyte (SPE) derived from iota carrageenan (IC) doped with sodium acetate (CH₃COONa). Films were prepared through a cost-efficient solution casting method. FTIR analysis verified successful polymer–salt complexation, indicated by notable shifts in characteristic functional groups. XRD patterns revealed a gradual reduction in crystallinity with increasing salt content, enhancing the amorphous phase that supports efficient ion mobility. Electrochemical Impedance Spectroscopy confirmed that the film containing 30 wt% CH₃COONa achieved the highest ionic conductivity of 1.93 × 10-5 S cm-1 at ambient temperature. The electrolyte also exhibited a broad electrochemical stability window of 3.6 V. A primary sodium-ion cell assembled with the optimized SPE delivered a stable open-circuit voltage of ~2.9 V, highlighting its promise for clean, resilient, and sustainable energy technologies.

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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Europium doped silicon (oxy)carbonitride (Si(O)CN) thin films were fabricated using an integrated electron cyclotron resonance plasma-enhanced chemical vapor deposition system combined with in situ magnetron sputtering. Post-deposition annealing was performed from 800 °C to 1200 °C to investigate europium activation within the Si(O)CN matrix. Room-temperature photoluminescence revealed visible bright red emission attributed to the intra 4 f transition of Eu³⁺ ions, prominently observed in films annealed at 1100 °C and 1200 °C. A detailed compositional analysis was performed with a combination of Rutherford backscattering spectrometry and elastic recoil detection analysis showing nearly 7 at% of europium in the luminescent film. The presence of crystalline phases from the high temperature annealed samples was confirmed by X-ray diffraction analysis. These investigations were conducted to assess the feasibility of amorphous Si(O)CN as a thermally and chemically stable, silicon-compatible host for rare-Earth doping. Europium doped Si(O)CN can offer promising potential for visible light emission in next generation integrated photonic and optoelectronic devices.

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Bifacial photovoltaic (PV) cells present a promising solution for enhanced energy harvesting in diverse environments, particularly for powering the proliferating network of low-energy Internet of Things (IoT) devices. This work details the numerical optimization of a novel bifacial cell based on a tunable CZT_1−xG_xSe absorber for dual indoor-outdoor applications. Using SCAPS-1D and RCWA simulations, the cell structure was systematically optimized by tuning key parameters, including germanium content, buffer layer, back contact, absorber properties, and an anti-reflection coating. The buffer layer material was selected to ensure optimal band alignment with the absorber, thereby minimizing non-radiative recombination. Meanwhile, the absorber thickness was optimized to balance photon absorption against the increase in series resistance. The cell’s performance was evaluated under 36 indoor wall colors and various outdoor ground albedos. Under indoor illumination, the optimized cell delivers an output power of 58.93 mW·cm⁻² (halogen) and 297 μW·cm⁻² (LED), sufficient to power a range of IoT sensors. Under outdoor AM1.5 G illumination, the output power ranges from 75.69 mW·cm⁻² (snow albedo) to 35.51 mW·cm⁻² (soil albedo). This study establishes a robust design framework for a versatile, high-efficiency PV cell, paving the way for sustainable power sources in smart buildings and embedded electronics.

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The radiation tolerance of single-crystal diamond devices was investigated under 10 MeV proton irradiation. Schottky barrier diodes (SBDs) and ITO/diamond heterojunction diodes were fabricated on boron-doped diamond substrates with a 10 μm lightly doped drift layer and exposed to proton fluences from 1.0 × 10¹³ to 1.6 × 10¹⁴ cm⁻². Irradiation induced increased on-resistance, reduced saturation current, and enhanced reverse leakage, with heterojunction devices showing greater degradation due to the vulnerability of the ITO layer and interface. Capacitance–voltage measurements revealed carrier removal rates of 171, 65, and 43 cm⁻¹ for fluences of 1.0 × 10¹³, 6.0 × 10¹³, and 1.6 × 10¹⁴ cm⁻², respectively, confirming diamond’s superior radiation hardness compared to Si, GaN, and Ga₂O₃. This resilience is attributed to diamond’s high atomic displacement energy, which limits lattice damage. These results demonstrate the potential of single-crystal diamond devices for radiation-hard power electronics and high-radiation environments.

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This paper proposes a gap-type metal-semiconductor-metal (MSM) phototransistor architecture based on lead sulfide quantum dots (PbS QDs) for room-temperature infrared (IR) thermal sensing applications. Owing to their tunable bandgap, strong IR absorption, and simple fabrication, PbS QDs are promising candidates for low-cost photodetection. The devices with PbS QDs exhibiting peak absorptions at 940 and 1600 nm were fabricated and compared. The 1600 nm device demonstrated a lower detectable temperature threshold and a linear photocurrent–temperature response above 150 °C, whereas the 940 nm device required over 300 °C. The enhanced performance of the 1600 nm device arises from its narrower bandgap, enabling stronger IR absorption and higher responsivity. However, the larger QD size and higher defect density result in a slower total response time (13.21 s) compared with the 940 nm device (157 μs). Consequently, the 940 nm device is suitable for real-time monitoring of high-temperature objects, while the 1600 nm device is preferable for static or slowly varying thermal radiation. These findings highlight the potential of PbS QD–based gap-type MSM photodetectors to achieve extended room-temperature IR sensing without external cooling, providing a feasible approach for low-cost and uncooled thermal imaging applications.

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The growth and optimization of Al(In)GaN back barrier by MOCVD for InAlGaN-based heterostructures is successfully demonstrated. At zero growth temperature gap (which was defined by ΔT_g = ∣T_g,channel-T_g,BB∣), the coherent growth of the back barrier was confirmed by perfectly ordered atoms, sharp interface quality, and absence of threading dislocations at the buffer/back-barrier/channel interfaces, including the smoothest surface of heterostructures. The electron transport properties of InAlGaN/GaN heterostructures were consistently affected by the growth temperature of the back barrier. Significant increase of electron mobility from 1560 to 1740 (cm² Vs⁻¹) and decrease of sheet carrier density from 1.57  ×  10¹³ to 1.31  ×  10¹³ (cm⁻²) were attributed to the improvement of electron confinement by adapting a thin ( 3.5 nm) optimized Al(In)GaN back barrier to the conventional InAlGaN/GaN heterostructure. XPS chemical shifts of the N1s core level and band alignment calculation have also confirmed the influence of the growth temperature of the back barrier on the electron confinement. Moreover, a large positive shift of the threshold voltage (2 V), a considerable increase in maximum transconductance from 180 to 216 (mS mm⁻¹), and suppression of the Kink effect of the devices were realized, which paves the way for the employment of the Al(In)GaN back barrier for high-frequency applications.

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Vertical p/p+ single-crystal diamond rectifiers were fabricated using a 5 μm boron-doped drift layer on a heavily doped substrate. We investigated the effect of different Schottky metal contacts (Ti, Ni, Cr, Pt, Au) on device performance, as well as use of an n-type indium tin oxide (ITO) layer to form a heterojunction. The Schottky barrier heights showed only a weak dependence on metal work function, consistent with significant Fermi-level pinning at the metal–diamond interface. Among the Schottky rectifiers, Ni/Au contacts demonstrated the best performance with low ideality factors (<1.1), good adhesion, and a maximum reverse breakdown voltage of 512 V. This resulted in an on-resistance (R_ON) of 11 mΩ⋅cm² and a power figure-of-merit (FOM) of 21.8 MW cm⁻². The ITO-diamond heterojunction rectifiers showed superior performance, achieving a breakdown voltage of 898 V with an on-resistance of 11 mΩ⋅cm² and a power FOM of 73.3 MW cm⁻². Our results highlight the crucial role of interfacial engineering in maximizing the performance of diamond power devices and demonstrate their potential for high-power, high-voltage applications.

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Area-selective atomic layer deposition (AS-ALD) has garnered considerable interest over the past decade due to its potential to enable bottom-up fabrication of nanostructures with atomic-scale precision, eliminating the need for complex multiple patterning and lithographic processes that often introduce alignment challenges. Selective deposition is achieved by facilitating nucleation and growth on the targeted growth area (GA) while chemically passivating the non-growth area (NGA) to inhibit film formation. This study explores the inhibition performance of two small molecular inhibitors (SMIs) dimethylamino-trimethylsilane (DMATMS) and bis(dimethylamino)dimethylsilane (BDMADMS) were evaluated, for area-selective ALD (AS-ALD) of Ru on the surface consisted with SiO₂ and W using a carbonyl-based Ru precursor and O₂ as an oxidant at 250 °C. BDMADMS, applied via spin-coating and baking, enabled selective Ru deposition on W surfaces while effectively suppressing nucleation and deposition on SiO₂ surfaces for up to 500 ALD cycles, in contrast, DMATMS dip provided short-term inhibition, but Ru was later deposited on SiO₂. We found that BDMADMS forms a stable inhibitor layer on SiO₂, exhibiting strong chemical stability and effectively protecting the surface from oxidative environments, thereby preventing Ru deposition, while DMATMS forms a less stable inhibitor layer on SiO₂, which degrades under oxidative conditions, leading to the loss of surface passivation and subsequent Ru deposition. Finally, optimized AS-ALD of Ru was achieved on three-dimensional SiO₂ and W patterned surface using BDMADMS as a SMI, where Ru selectively deposited only on the W regions, demonstrating precise control over nucleation and deposition, its promise for advanced integration strategies.

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In this work, we investigate the effects of metal sidewall (MSW) source/drain (S/D) on basic current mirror (CM) circuits constructed from vertically arranged gate-all-around (GAA) nanosheet (NS) FETs. The performance of circuits with (w/) and without (w/o) MSW S/D is examined using 3D numerical device-circuit simulations. The electrostatic potential distribution in the studied structures is significantly affected by parasitic resistance. Incorporating MSW S/D reduces parasitic resistance and strongly influences the output characteristics, depending on the basic CM channel number. In terms of the current of basic CM, five channels w/ MSW S/D is better than eleven channels w/o MSW S/D, highlighting the critical need for MSWs to reduce source/drain parasitic resistance. Cascode CMs exhibit similar trends as CMs, and the use of MSW S/D allows for an increased number of channels in cascode configurations. For cascode CM with ten channels, the MSW S/D enables it to conduct a current that is three times higher.

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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.

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.

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.

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.

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.

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.

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.

The ability to achieve near-atomic precision in etching different materials when transferring lithographically defined templates is a requirement of increasing importance for nanoscale structure fabrication in the semiconductor and related industries. The use of ultra-thin gate dielectrics, ultra thin channels, and sub-20 nm film thicknesses in field effect transistors and other devices requires near-atomic scale etching control and selectivity. There is an emerging consensus that as critical dimensions approach the sub-10 nm scale, the need for an etching method corresponding to Atomic Layer Deposition (ALD), i.e. Atomic Layer Etching (ALE), has become essential, and that the more than 30-year quest to complement/replace continuous directional plasma etching (PE) methods for critical applications by a sequence of individual, self-limited surface reaction steps has reached a crucial stage. A key advantage of this approach relative to continuous PE is that it enables optimization of the individual steps with regard to reactant adsorption, self-limited etching, selectivity relative to other materials, and damage of critical surface layers. In this overview we present basic approaches to ALE of materials, discuss similarities/crucial differences relative to thermal and plasma-enhanced ALD, and then review selected results on ALE of materials aimed at pattern transfer. The overview concludes with a discussion of opportunities and challenges ahead.

This paper introduces a novel device called the Gate All Around Engineered Gallium Nitride Field Effect Transistor (GAAE-GANFET), designed specifically for label-free biosensing applications. This innovative gate-all-around engineering in GANFET integrates various device engineering techniques, such as channel engineering, gate engineering, and oxide engineering, to enhance biosensing performance. The channel engineering techniques refer to the use of a gallium nitride channel with a step-graded doping profile, divided into three distinct regions. In contrast, the gate engineering technique refers to the cylindrical split-gate-underlap architecture. The oxide engineering technique involves stacking Al₂O₃ and HfO₂. Moreover, this biosensor incorporates two-sided gate underlap cavities that facilitate the immobilization of biomolecules. These open cavities not only provide structural stability but also simplify the fabrication process to a significant extent. The viability of this biosensor as a label-free biosensor has been evaluated using an antigen and an antibody from the Avian Influenza virus and DNA as the target biomolecules. The proposed analytical model and TCAD simulation results are in excellent agreement, demonstrating the reliability of the proposed device. Additionally, the biosensor’s sensitivity, which depends on cavity length, doping concentration, gate metal work function, and temperature variation, has been thoroughly explored. The gate-all-around structure, along with the integration of tri-step graded doping, GaN as the channel material, gate oxide stacking, and dual open cavity structure in the proposed biosensor, leads to significantly improved biosensing capabilities.

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.