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Molybdenum disulfide (MoS2), a semiconducting two-dimensional layered transition metal dichalcogenide (2D TMDC), with attractive properties enables the opening of a new electronics era beyond Si. However, the notoriously high contact resistance (RC) regardless of the electrode metal has been a major challenge in the practical applications of MoS2-based electronics. Moreover, it is difficult to lower RC because the conventional doping technique is unsuitable for MoS2 due to its ultrathin nature. Therefore, the metal–insulator–semiconductor (MIS) architecture has been proposed as a method to fabricate a reliable and stable contact with low RC. Herein, we introduce a strategy to fabricate MIS contact based on atomic layer deposition (ALD) to dramatically reduce the RC of single-layer MoS2 field effect transistors (FETs). We utilize ALD Al2O3 as an interlayer for the MIS contact of bottom-gated MoS2 FETs. Based on the Langmuir isotherm, the uniformity of ALD Al2O3 films on MoS2 can be increased by modulating the precursor injection pressures even at low temperatures of 150 °C. We discovered, for the first time, that film uniformity critically affects RC without altering the film thickness. Additionally, we can add functionality to the uniform interlayer by adopting isopropyl alcohol (IPA) as an oxidant. Tunneling resistance across the MIS contact is lowered by n-type doping of MoS2 induced by IPA as the oxidant in the ALD process. Through a highly uniform interlayer combined with strong doping, the contact resistance is improved by more than two orders of magnitude compared to that of other MoS2 FETs fabricated in this study. [ABSTRACT FROM AUTHOR]

The enhancement-mode AlGaN/GaN metal insulator semiconductor high electron mobility transistor (MIS-HEM) with recessed gate structure is comprehensively studied by using Silvaco TCAD software. The effects of etching depth of AlGaN barrier layer, gate length, sort and thickness of gate dielectric layer on device performance are explored. The outcomes from the simulation indicate that the enhanced device is capable of attaining a threshold voltage of +1 V, a substantial drain saturation current of 1.38 A/mm, and an elevated peak transconductance of 498 mS/mm. It has been observed that the gate recess depth substantially boosts the transconductance, achieving a maximum value of gmmax at 498 mS/mm.The value significantly surpasses that exhibited by the traditional AlGaN/GaN MIS-HEMT. The threshold voltage of Al0.18Ga0.82N TBL recessed gate MIS-HEMT is +1 V. Furthermore, in comparison to the conventional MIS-HEMT device, the drain saturation current experiences an augmentation by about 9.5%. TCAD simulation results show that this HEMT structure is more effective than conventional HEMT in terms of enhanced mode operation and device parameters. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting provides a scalable and integrated platform to harness renewable solar energy for green hydrogen production. The practical implementation of PEC systems hinges on addressing three critical challenges: enhancing energy conversion efficiency, ensuring long-term stability, and achieving economic viability. Metal–insulator–semiconductor (MIS) heterojunction photoelectrodes have gained significant attention over the last decade for their ability to efficiently segregate photogenerated carriers and mitigate corrosion-induced semiconductor degradation. This review discusses the structural composition and interfacial intricacies of MIS photoelectrodes tailored for PEC water splitting. The application of MIS heterostructures across various semiconductor light-absorbing layers, including traditional photovoltaic-grade semiconductors, metal oxides, and emerging materials, is presented first. Subsequently, this review elucidates the reaction mechanisms and respective merits of vacuum and non-vacuum deposition techniques in the fabrication of the insulator layers. In the context of the metal layers, this review extends beyond the conventional scope, not only by introducing metal-based cocatalysts, but also by exploring the latest advancements in molecular and single-atom catalysts integrated within MIS photoelectrodes. Furthermore, a systematic summary of carrier transfer mechanisms and interface design principles of MIS photoelectrodes is presented, which are pivotal for optimizing energy band alignment and enhancing solar-to-chemical conversion efficiency within the PEC system. Finally, this review explores innovative derivative configurations of MIS photoelectrodes, including back-illuminated MIS photoelectrodes, inverted MIS photoelectrodes, tandem MIS photoelectrodes, and monolithically integrated wireless MIS photoelectrodes. These novel architectures address the limitations of traditional MIS structures by effectively coupling different functional modules, minimizing optical and ohmic losses, and mitigating recombination losses. [ABSTRACT FROM AUTHOR]

Light‐driven micro/nanorobots (LMNRs) are tiny, untethered machines with great potential in fields like precision medicine, nano manufacturing, and various other domains. However, their practicality hinges on developing light‐manipulation strategies that combine versatile functionalities, flexible design options, and precise controllability. Our study introduces an innovative approach to construct micro/nanorobots (MNRs) by utilizing micro/nanomotors as fundamental building blocks. Inspired by silicon Metal‐Insulator‐Semiconductor (MIS) solar cell principles, we design a new type of optomagnetic hybrid micromotors (OHMs). These OHMs have been skillfully optimized with integrated magnetic constituent, resulting in efficient light propulsion, precise magnetic navigation, and the potential for controlled assembly. One of the key features of the OHMs is their ability to exhibit diverse motion modes influenced by fracture surfaces and interactions with the environment, streamlining cargo conveyance along "micro expressway"—the predesigned microchannels. Further enhancing their versatility, a template‐guided assembly strategy facilitates the assembly of these micromotors into functional microrobots, encompassing various configurations such as "V‐shaped", "N‐shaped", and 3D structured microrobots. The heightened capabilities of these microrobots, underscore the innovative potential inherent in hybrid micromotor design and assembly, which provides a foundational platform for the realization of multi‐component microrobots. Our work moves a step toward forthcoming microrobotic entities boasting advanced functionalities. [ABSTRACT FROM AUTHOR]

In this work, the design, fabrication, static device testing, and double‐pulse switching performance of multi‐finger D‐mode GaN metal–insulator–semiconductor high‐electron‐mobility transistors (MISHEMTs) on silicon are discussed. Utilizing an metal‐organic chemical vapor deposition‐grown GaN high‐electron‐mobility transistors stack with a superlattice buffer, field‐plated devices with a meandering gate geometry and a total gate width of 30 mm are fabricated. Plasma enhanced chemical vapor deposition SiNx is used as the gate dielectric, followed by an optimized bilayer SiNx passivation scheme. Devices with 100 μm gate width have an ON/OFF ratio of ≈108. They are analyzed for dynamic Ron (normalized Ron = 3 at 100 μs) and time‐dependent dielectric breakdown for gate reliability, resulting in a β value of 2.65 from the Weibull plot. Devices with a 30 mm gate width exhibit a maximum ON current of 8 A at zero gate voltage and a three‐terminal breakdown of ≈500 V. The devices are diced, wire‐bonded to a printed circuit board, and a double‐pulsed test is performed for switching transient characterization under clamped inductive load. The OFF‐state and ON‐state energy loss are estimated to be Eon = 14 μJ and EOFF = 27 μJ, respectively, when switched at 5 A, 50 V. In this study, the potential of GaN MISHEMTs with bilayer SiNx passivation for low‐power D‐mode switching applications (5 A, 50 V) is demonstrated. [ABSTRACT FROM AUTHOR]

GaN metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs) with scandium aluminum nitride Sc0.2Al0.8N/SiNX composite gate dielectric were demonstrated with improved device performance in terms of current density, on-resistance, breakdown voltage, gate leakage, and current collapse. GaN MIS-HEMTs with single-layer Sc0.2Al0.8N or SiNX were also fabricated as reference. Notably, the current collapse was reduced from ∼38.8% in GaN MIS-HEMTs with single-layer SiNX dielectric to ∼4.9% in the device with composite gate dielectric. The insertion of the thin SiNX layer can mitigate the surface damage due to the ScAlN sputtering process and significantly reduce the interface state density. Furthermore, the high valence band offset of Sc0.2Al0.8N/SiNX of 0.78 eV also plays a key role in the suppression of hole injection and gate leakage current. This work shows the effectiveness of the Sc0.2Al0.8N/SiNX composite gate dielectric and can serve as an important reference for future developments of high-performance reliable GaN HEMTs for power and RF electronics. [ABSTRACT FROM AUTHOR]

III-nitride heterostructure-based metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs), compared with Schottky and p-GaN gate HEMTs, have demonstrated significant potential in the next-generation high-power electronic devices due to their exceptional gate reliability. This study presents a comprehensive investigation of threshold voltage (VTH) instability in III-nitride heterostructure-based MIS-HEMTs, with a specific emphasis on the interfaces of the multi-heterostructures. Two widely studied amorphous materials, namely, Al2O3 and SiNx, have been extensively examined as primary gate insulators in GaN-based MIS-HEMTs. To efficiently remove native oxides from the (Al)GaN surface, a novel in situ high-temperature remote plasma pretreatment (RPP) technique has been developed. This technique involves sequential application of NH3/N2 plasmas on the (Al)GaN surface before depositing the gate insulators using plasma-enhanced atomic layer deposition. The remarkable RPP process has proven to be a highly effective method for revealing atomic steps on the GaN surface, irrespective of whether the surface has undergone oxidation or etching processes. To further enhance the interface quality and potentially reduce bulk traps in the gate insulator, optimization of deposition temperature and post-deposition annealing conditions have been explored. Additionally, an electron-blocking layer, such as SiON, is incorporated into the MIS-HEMTs to prevent electron injection into bulk traps within the insulator. Novel characterization techniques including constant-capacitance and isothermal-mode deep-level transient spectroscopy have also been developed to explore the failure mechanisms in MIS-HEMTs. These techniques allow for the differentiation between bulk traps in the GaN epitaxy and those present within the gate insulators. This in-depth physical understanding provides valuable insights into the sources of failure in GaN-based MIS-HEMTs. [ABSTRACT FROM AUTHOR]

This work presents the green synthesis of iron oxide nanoparticles (IONPs) using Baccharis salicifolia extract and their incorporation in mesoporous silica MCM-41, obtaining an MCM-41@IONP composite. The MCM-41@IONP composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption and desorption, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The use of the natural reducing agent Baccharis salicifolia resulted in nanoparticles with an average size of 31 nm. Furthermore, we showcase the application of the MCM-41@IONP nanocomposite in a metal–insulator–semiconductor (MIS) diode, which was fabricated at room temperature. The current–voltage and capacitance–voltage curves of the MIS diode were carefully measured and subjected to detailed analysis. The results demonstrate the potential utility of MCM-41@IONP nanocomposite-based MIS diodes, suggesting their applicability in the design of biosensors or as discrete components in electronic devices. [ABSTRACT FROM AUTHOR]

The burgeoning interest in non-classical MOSFET devices for low power applications and their latest incorporation in the newer technology node necessitate a study of Negative Capacitance Field Effect Transistors (NCFETs) in Radio Frequency applications. This work explores the comparative analysis of RF/analog performance of single gate NCFET (SG-NCFET) and highly doped double pocket double gate NCFET (HDDP-DG-NCFET) using performance parameters such as cut-off frequency (fT), transconductance frequency product (TFP) and transconductance generation factor (TGF). The Metal Ferroelectric Insulator Semiconductor based HDDP-DG-NCFET excels SG-NCFET in terms of enhanced performance in TGF and TFP. In addition, several important distortion parameters, such as intermodulation distortion and linearity, are also investigated for these devices. The behavior of distortion and linearity indices such as gm2, gm3 (higher-order transconductance), IIP3 (3rd order power-intercept point), higher order voltage intercept points (VIP2 and VIP3), 1 dB compression point, and total harmonic distortion is analyzed, which shows that HDDP-DG-NCFET exhibits distortion less performance. The influence of ferroelectric thicknesses and temperature on the RF/analog and linearity performance are also explored and described. The HDDP-DG-NCFET exhibits an ON current of 2.1 × 10−3 A/ μ m, current switching ratio of 0.79 × 1010, gm of 18.9 mS, fT of 2.65 THz, TFP of 64 THz/V, which is 55.56%, 111.27 times, 134.79%, 55.88%, 255.56%, respectively higher than SG-NCFET device. In addition, the subthreshold swing and OFF current of HDDP-DG-NCFET are 25.5 mV/decade and 2.65 × 10−13 A/ μ m, which is lesser than SG-NCFET. Moreover, it is witnessed that as the temperature rises from 250 to 400 K, RF/analog metrics are worsened while the linearity performance parameters are enhanced. Furthermore, it is observed that the proposed HDDP-DG-NCFET is linear compared to SG-NCFET with a lower magnitude of higher-order harmonics. Finally, these findings reveal that at lower voltages, HDDP-DG-NCFET outperforms SG-NCFET, evincing potential use of the same in RF applications. [ABSTRACT FROM AUTHOR]

The utilization of a zirconium oxide (ZrO2) thin film as the insulator in a metal–insulator–semiconductor (MIS) capacitor to enhance the characteristics of thin‐film transistors is investigated. Although the high crystallinity of ZrO2 is favorable to achieving higher capacitance density in metal–insulator–metal capacitors with ZrO2 thin films, it decreases the capacitance with increasing applied bias in Mo/ZrO2/InGaZnO (IGZO)‐structured MIS capacitors. Through comprehensive physical, chemical, and electrical characterizations, this study investigated the mechanism underlying the decreasing capacitance with increasing the applied bias in the accumulation state of the Mo/ZrO2/IGZO‐structured MIS capacitor depending on the crystallinity of ZrO2. Furthermore, the investigation identifies the optimal crystal structure of ZrO2 thin films for IGZO‐based MIS capacitors, highlighting the importance of forming meso‐crystalline structures in high dielectric constant (k) materials to enhance the k value and mitigating the decrease in capacitance caused by the accumulated carrier loss through grain boundaries of ZrO2. [ABSTRACT FROM AUTHOR]

As diamond possesses only deep dopants, certain conventional physics and characterization methods are not applicable to diamond devices, owing to the explicit or implicit assumption of shallow dopants. To resolve this limitation, the capacitance–voltage (C–V) characteristics of metal–insulator–semiconductor (MIS) capacitors formed on a semiconductor substrate with deep and compensating dopants were successfully formulated. Based on these equations, methods for accurately estimating the MIS capacitor properties were developed and validated through their application in the analysis of an actual MIS capacitor formed on a boron-doped hydrogen-terminated diamond substrate. The high-frequency C–V characteristic of the capacitor exhibited a prominent dip specific to deep dopants. However, the dip depth was considerably shallower than theoretically expected. This C–V characteristic was accurately reproduced theoretically, assuming the presence of a surficial diamond layer that contains acceptors with an activation energy of 0.23 eV, which is less than the value 0.37 eV for boron, and has a thickness of the extrinsic Debye length (40 nm in this study) or larger. The insulator charge of the MIS capacitor was estimated as −4.6 × 1012 cm−2 in units of electronic charge, which is sufficiently large to induce two-dimensional hole gas. The interface-state density was 1.4 × 1012 cm−2 eV−1 for interface-state energies of 0.3–0.5 eV above the valence band maximum. Hence, the proposed methodology and the possible presence of the reduced activation energy layer will guide the development of diamond-based devices. [ABSTRACT FROM AUTHOR]

The authors report a novel structure to improve the high‐frequency performance of nitrogen‐polar GaN deep‐recess high electron mobility transistors (HEMTs) wherein a timed plasma etch was used to tailor the profile of the gate dielectric. A favourable trade‐off between gate fringing capacitance and transconductance was established, resulting in an improved current gain cutoff frequency times gate length (ft·LG) figure of merit compared to standard Schottky‐gate and metal‐insulator‐semiconductor (MIS) HEMTs. The etched gate dielectric MISHEMT demonstrated a maximum ft·LG of 15.0 GHz·µm for an LG of 100 nm. [ABSTRACT FROM AUTHOR]

In this study, a series of ∼26 nm thick hafnium oxide films doped with different concentrations of Mg were prepared by the chemical solution deposition method. With the increase of Mg concentration, the film undergoes a phase transition from monoclinic, through orthorhombic, and then to cubic. Metal–insulator–semiconductor capacitors were fabricated, and the ferroelectricity was verified for films doped with an Mg concentration of 0.4–3.7 mol. %. For the film doped with 2.3 mol. % Mg, the remanent polarization is 16.4 μC/cm2 after the wake-up process, and 76.1% of the initial 2Pr value can be maintained after 107 cycles of bipolar field cycling. All the results show that Mg is a promising dopant to stabilize the ferroelectricity of hafnium oxide films. [ABSTRACT FROM AUTHOR]

The Vth stability and gate reliability of AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) with alternating O2 plasma treatment were systematically investigated in this article. It was found that the conduction band offset at the Al2O3/AlGaN interface was elevated to 2.4 eV, which contributed to the suppressed gate leakage current. The time-dependent dielectric breakdown (TDDB) test results showed that the ALD-Al2O3 with the alternating O2 plasma treatment had better quality and reliability. The AlGaN/GaN MIS-HEMT with the alternating O2 plasma treatment demonstrated remarkable advantages in higher Vth stability under high-temperature and long-term gate bias stress. [ABSTRACT FROM AUTHOR]

In order to search for possible residual minor phases in the Y-Ba-Cu-O family, powdered mixtures of Y2O3 + BaCO3 + CuO and, independently, superconducting compound YBa2Cu3O7−x have been treated in evacuated cells and elevated temperatures. YBa2Cu3O7−x was reduced to YBa2Cu3O5 by use of the special home-designed Taconis–Knudsen vacuum device. Subsequent doping by oxygen converts produced insulator YBa2Cu3O5 to semiconductor or metal YBa2Cu3O5+x (0 < x < 0.3). In addition to YBa2Cu3O5, 0.05 volume percent of the minor delafossite phase Y2Cu2O4 was spotted in the powder mixture 1/2 Y2O3 + 2BaCO3 + 6Cu2O, heated up to 818 °C in an inert gas atmosphere. An attempt to prepare the insulating bulk delafossite samples was successful, and subsequent doping by oxygen produced novel metallic phases. [ABSTRACT FROM AUTHOR]

This article presents the utilization of the chemical–mechanical polishing (CMP) method to fabricate high-performance N-polar GaN/AlGaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) through layer transfer technology. The nucleation and buffer layers were removed via CMP to attain a pristine N-polar GaN surface with elevated smoothness, featuring a low root-mean-square (RMS) roughness of 0.216 nm. Oxygen, carbon, and chlorine impurity elements content were low after the CMP process, as detected via X-ray photoelectron spectroscopy (XPS). The electrical properties of N-polar HEMTs fabricated via CMP exhibited a sheet resistance (Rsh) of 244.7 Ω/sq, a mobility of 1230 cm2/V·s, and an ns of 2.24 × 1013 cm−2. Compared with a counter device fabricated via inductively coupled plasma (ICP) dry etching, the CMP devices showed an improved output current of 756.1 mA/mm, reduced on-resistance of 6.51 Ω·mm, and a significantly reduced subthreshold slope mainly attributed to the improved surface conditions. Meanwhile, owing to the MIS configuration, the reverse gate leakage current could be reduced to as low as 15 μA/mm. These results highlight the feasibility of the CMP-involved epitaxial layer transfer (ELT) technique to deliver superior N-polar GaN MIS-HEMTs for power electronic applications. [ABSTRACT FROM AUTHOR]

The current conduction in negatively biased metal/Al2O3/diamond capacitors with various gate materials and diamond surface terminations was comprehensively characterized by assuming a space-charge-controlled field emission (SCC-FE) process, yielding the following results. The current-feeding carriers were field-emitted from the electrode that had a barrier height lower than that of the opposing electrode. Specifically, in an Au-gate oxygen-terminated diamond capacitor, holes were likely to be emitted from the Al2O3/diamond interface states, whereas, in Al-gate oxygen-terminated, Au-gate hydrogen-terminated, and Al-gate hydrogen-terminated diamond capacitors, electrons were emitted from the gate. The barrier heights at the Al/Al2O3 and Au/Al2O3 interfaces were estimated as 1.6–1.7 and 2.8 eV, respectively. However, the analysis of the hole emission from the interface states is left for future studies. Although the substrate of the oxygen-terminated diamond capacitor remained weakly depleted even for highly negative gate voltages, the conduction current was observed as mentioned earlier. To analyze the mechanism for this conduction, the diffusion and drift currents in the depleted substrate were quantitatively estimated, ascribing the current conduction to the diffusion current. As these results could not be obtained by using the conventional graphical methods based on model-specific plots, such as the Fowler–Nordheim and Poole–Frenkel plots, the SCC-FE analysis proved to be a powerful tool for investigating the current conduction in metal-insulator-semiconductor capacitors. [ABSTRACT FROM AUTHOR]

The ferroelectric negative capacitance (NC) draws a great deal of attention for low‐power negative capacitance field‐effect transistors (NCFET) and NC capacitors. The fabrication of steep‐slope FET (subthreshold swing < 60mVdec−1) is reported, followed by modeling approaches. While the device fabrication favors a ferroelectric gate structure without interlayer metal, many NCFET models adopt interlayer metal between the ferroelectric layer and metal–insulator–semiconductor structure. The metal interlayer averages out spatial variation in the ferroelectric polarization, enabling a compact charge‐based relation between the layers. In addition, the approach assumes that the NC effect emerges from the ferroelectric layer regardless of the metal interlayer, which is not necessarily probable. This work reinvestigates the possible NC effect in ferroelectric–dielectric capacitors connected by a metal interlayer. The experiment confirms that the NC effect in the metal–ferroelectric–dielectric–metal structure does not appear in the metal–ferroelectric–metal–dielectric–metal structure. These results are inconsistent with the multidomain‐1D Landau–Ginzburg‐Devonshire model. In contrast, the suppression of the NC effect in the structure is fully explained by the advanced inhomogeneous stray‐field energy model, which simulates the dynamic evolution of polarization and screening charges. Therefore, an NCFET with a metal interlayer is impractical. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate the high performance of β-Ga2O3 metal–insulator–semiconductor (MIS) diodes. An ultrathin boron nitride (BN) interlayer is directly grown on the Ga2O3 substrate by pulsed laser deposition. X-ray photoelectron spectroscopy, Raman spectroscopy, and high-resolution transmission electron microscopy confirm the existence of a 2.8 nm BN interlayer. Remarkably, with the insertion of the ultrathin BN layer, the breakdown voltage is improved from 732 V for Ga2O3 Schottky barrier diodes to 1035 V for Ga2O3 MIS diodes owing to the passivated surface-related defects and reduced reverse leakage currents. Our approach shows a promising way to improve the breakdown performance of Ga2O3-based devices for next-generation high-power electronics. [ABSTRACT FROM AUTHOR]

A HfO2/Al2O3/AlN stack deposited in a plasma-enhanced atomic layer deposition system is used as the gate dielectric for GaN metal–insulator–semiconductor structures. Prior to the deposition, in situ remote plasma pretreatments (RPPs) with O2, NH3, and NH3–O2 (in sequence) were carried out. Frequency-dependent capacitance–voltage (C–V) measurements reveal that for all the RPP-treated samples, the interface trap density Dit was significantly reduced compared to the sample without RPP. In particular, the NH3-treated sample exhibits an extremely low Dit of ∼1011 cm−2·eV−1 from EC − 0.31 eV to EC − 0.46 eV. To characterize the interface traps at deeper levels, the transfer pulsed I–V measurement was employed further. In the energy range of EC − ET > 0.54 eV, the interface trap charge density Qit of various samples demonstrates the following order: NH3 RPP < NH3–O2 RPP < O2 RPP < without RPP. By adjusting multiple pulse widths, the Dit derived from the Qit result matches the C–V measurement precisely. Moreover, X-ray photoelectron spectroscopy analysis of the Ga 3d core-level indicates that NH3 RPP facilitates the conversion of Ga2O into GaN at high RF power of 2500 W, whereas O2 RPP mainly oxidizes GaN to relatively stable Ga2O3. Combined with the C–V and pulsed I–V measurements, it is confirmed that a strong positive correlation exists between Ga2O and the interface traps, rather than Ga2O3. [ABSTRACT FROM AUTHOR]

There is a growing interest in new semiconductor nanostructures for future high-density high-performance flexible electronic devices. Two-dimensional conjugated microporous polymers (2D-CMPs) are promising candidates because of their inherent optoelectronic properties. Here, we are reporting a novel donor–acceptor type 2D-CMP based on Pyrene and Isoindigo (PI) for a potential nano-scale charge-trapping memory application. We exfoliated the PI polymer into ~ 2.5 nm thick nanoparticles (NPs) and fabricated a Metal–Insulator–Semiconductor (MIS) device with PI–NPs embedded in the insulator. Conductive AFM (cAFM) is used to examine the confinement mechanism as well as the local charge injection process, where ultrathin high-κ alumina supplied the energy barrier for confining the charge carrier transport. We have achieved a reproducible on-and-off state and a wide memory window (ΔV) of 1.5 V at a relatively small reading current. The device displays a low operation voltage (V < 1 V), with good retention (104 s), and endurance (103 cycles). Furthermore, a theoretical analysis is developed to affirm the measured charge carriers' transport and entrapment mechanisms through and within the fabricated MIS structures. The PI–NPs act as a nanoscale floating gate in the MIS-based memory with deep trapping sites for the charged carriers. Moreover, our results demonstrate that the synthesized 2D-CMP can be promising for future low-power high-density memory applications. [ABSTRACT FROM AUTHOR]

Localized photoinduced electrochemiluminescence (PECL) is studied on photoanodes composed of Ir microbands deposited on n-Si/SiOx. We demonstrate that PECL microscopy precisely imaged the hole-driven heterogeneous photoelectrochemical reactivity. The method is promising for elucidating the local activity of photoelectrodes that are employed in solar energy conversion. [ABSTRACT FROM AUTHOR]

Hafnium oxide (HfO2) films are synthesized on silicon substrates using magnetron sputtering under various technological conditions. The results on the structural composition of HfO2 films and the electrical properties of metal–insulator–semiconductor heterostructures (Ni– HfO2–Si) based on them are presented. [ABSTRACT FROM AUTHOR]

We report on a method by which we can systematically extract spectroscopic information such as isotropic electron–nuclear hyperfine coupling constants from near-zero field magnetoresistance (NZFMR) spectra. The method utilizes a least squares fitting of models developed from the stochastic quantum Liouville equation. We applied our fitting algorithm to two distinct material systems: Si/SiO2 metal oxide semiconductor field effect transistors and a-Si:H metal insulator semiconductor capacitors. Our fitted results and hyperfine parameters are in reasonable agreement with existing knowledge of the defects present in the systems. Our work indicates that the NZFMR response and fitting of the NZFMR spectrum via models developed from the stochastic quantum Liouville equation could be a relatively simple yet powerful addition to the family of spin-based techniques used to explore the chemical and structural nature of point defects in semiconductor devices and insulators. [ABSTRACT FROM AUTHOR]

The research of two-dimensional (2D) Tellurium (Te) or tellurene is thriving to address current challenges in emerging thin-film electronic and optoelectronic devices. However, the study of 2D-Te-based devices for high-frequency applications is still lacking in the literature. This work presents a comprehensive study of two types of radio frequency (RF) diodes based on 2D-Te flakes and exploits their distinct properties in two RF applications. First, a metal-insulator-semiconductor (MIS) structure is employed as a nonlinear device in a passive RF mixer, where the achieved conversion loss at 2.5 GHz and 5 GHz is as low as 24 dB and 29 dB, respectively. Then, a metal-semiconductor (MS) diode is tested as a zero-bias millimeter-wave power detector and reaches an outstanding linear-in-dB dynamic range over 40 dB, while having voltage responsivities as high as 257 V ⋅ W−1 at 1 GHz (up to 1 V detected output voltage) and 47 V ⋅ W−1 at 2.5 GHz (up to 0.26 V detected output voltage). These results show superior performance compared to other 2D material-based devices in a much more mature technological phase. Thus, the authors believe that this work demonstrates the potential of 2D-Te as a promising material for devices in emerging high-frequency electronics. [ABSTRACT FROM AUTHOR]

This study is devoted to the study of metal–insulator–semiconductor (MIS) structures based on n-HgCdTe (MCT) grown by molecular beam epitaxy (MBE) in the NBνN configuration, intended for the development of infrared (IR) detectors with reduced dark currents for MWIR and LWIR spectral ranges. Seven types of MIS structures have been studied by the admittance spectroscopy method. It is shown that the measurements of the frequency dependences of the impedance of MIS devices make it possible to accurately determine the differential resistance of the barrier structure. It has been established that for one of the studied structures, the values of the differential resistance are determined by the bulk component of the dark current, while the surface leakage component does not significantly affect the measured impedance. It is shown that if the problem of passivation of mesa structures is solved, it is possible to fabricate efficient MWIR and LWIR nBn, NBνN detectors based on MBE HgCdTe with high threshold parameters. [ABSTRACT FROM AUTHOR]

Aluminum gallium nitride/gallium nitride (AlGaN/GaN) heterostructure devices have proven to be highly effective for high‐frequency power amplifiers and power switching applications with improved performance compared to those made with traditional silicon technology and other advanced semiconductor technologies. The development of enhancement‐mode (E‐mode) AlGaN/GaN high electron mobility transistors (HEMTs) and metal–insulator–semiconductor HEMTs (MIS‐HEMTs) has been a focus in recent years due to their potential applications. Arising from the concept of a flash‐memory‐like hybrid ferroelectric charge storage structure, the high‐performance hybrid ferroelectric charge storage gate (FEG) GaN HEMT has gradually gained a great deal of attention due to the concept being a useful and versatile tool to realize E‐mode operations. This article attempts to review the latest progresses in this technology, including alternative improvements and device characteristics. Future challenges for the E‐mode FEG‐HEMT are also discussed. [ABSTRACT FROM AUTHOR]

Silicon-based photodetectors are attractive as low-cost and environmentally friendly optical sensors. Also, their compatibility with complementary metal-oxide-semiconductor (CMOS) technology is advantageous for the development of silicon photonics systems. However, extending optical responsivity of silicon-based photodetectors to the mid-infrared (mid-IR) wavelength range remains challenging. In developing mid-IR infrared Schottky detectors, nanoscale metals are critical. Nonetheless, one key factor is the Fermi-level pinning effect at the metal/silicon interface and the presence of metal-induced gap states (MIGS). Here, we demonstrate the utilization of the passivated surface layer on semiconductor materials as an insulating material in metal-insulator-semiconductor (MIS) contacts to mitigate the Fermi-level pinning effect. The removal of Fermi-level pinning effectively reduces the Schottky barrier height by 12.5% to 16%. The demonstrated devices exhibit a high responsivity of up to 234 μA/W at a wavelength of 2 μm, 48.2 μA/W at 3 μm, and 1.75 μA/W at 6 μm. The corresponding detectivities at 2 and 3 μm are 1.17 × 108 cm Hz1/2 W−1 and 2.41 × 107 cm Hz1/2 W−1, respectively. The expanded sensing wavelength range contributes to the application development of future silicon photonics integration platforms. [ABSTRACT FROM AUTHOR]

The present work investigates the charge storage behaviors of the silicon nitride charge trapping (CT) films. Herein, the silicon nitride has been synthesized by a new green deep eutectic solvent (DES) for the first time. The nitride films with a new chemical route are deposited on silicon (Si) substrate using a homemade and cost-effective spin coating method (SCM). X-ray diffraction and scanning electron microscopy have been performed to study the crystallographic and surface morphological properties of the fabricated silicon nitride films. The deposited silicon nitride thin films confirm polycrystalline nature. It is revealed that the silicon nitride films using the DES can be developed efficiently on the Si substrate by the SCM at nearly room temperature. In this work, the charge storage properties of the prepared spin-coated silicon nitride-based metal–insulator-semiconductor (MIS) memory device of Ag/silicon nitride/p-silicon/Ag are also explored by quantifying the current–voltage (I–V) and capacitance–voltage (C–V) characteristics. The flat-band potentials of the MIS capacitor having the nitride film with two-layer cycle deposition are estimated to be 0.043 V and 0.22 V for 1st and 2nd scans, respectively. The large flat-band potentials of 0.79 V for 1st scan and 1.60 V for 2nd scan are estimated, respectively, for the MIS capacitor with six-layer deposition. The positive flat-band potential is owing to the trapped electrons by trap centers located in the fabricated silicon nitride CT films. Therefore, it is suggested that the silicon nitride films fabricated by an inexpensive and efficient SCM at low (nearly room) temperature can be employed as a CT layer in the memory cell. [ABSTRACT FROM AUTHOR]

Optimization of equipment structure and process conditions is essential to obtain thin films with the required properties, such as film thickness, trapped charge density, leakage current, and memory characteristics, that ensure reliability of the corresponding device. In this study, we fabricated metal–insulator–semiconductor (MIS) structure capacitors using HfO2 thin films separately deposited by remote plasma (RP) atomic layer deposition (ALD) and direct-plasma (DP) ALD and determined the optimal process temperature by measuring the leakage current and breakdown strength as functions of process temperature. Additionally, we analyzed the effects of the plasma application method on the charge trapping properties of HfO2 thin films and properties of the interface between Si and HfO2. Subsequently, we synthesized charge-trapping memory (CTM) devices utilizing the deposited thin films as charge-trapping layers (CTLs) and evaluated their memory properties. The results indicated excellent memory window characteristics of the RP-HfO2 MIS capacitors compared to those of the DP-HfO2 MIS capacitors. Moreover, the memory characteristics of the RP-HfO2 CTM devices were outstanding as compared to those of the DP-HfO2 CTM devices. In conclusion, the methodology proposed herein can be useful for future implementations of multiple levels of charge-storage nonvolatile memories or synaptic devices that require many states. [ABSTRACT FROM AUTHOR]

Aluminum-doped lanthanum phosphate (LaPO4:Al) nanoparticles were synthesized using a simple co-precipitation technique. The x-ray diffraction patterns show that all of the collected samples have a monoclinic structure with crystallite size (D) increasing from 13 to 17 nm as the Al-doping concentration increases, whereas the band gap values dropped from 5.46 eV to 3.93 eV with the increased Al-doping concentration. The effect of I–V electrical performance was methodically investigated in 10% Al-doped LaPO4-based metal–insulator–semiconductor (MIS)-type Schottky barrier diodes (SBDs). The experimental results reveal that the changes in the barrier height of 0.772 eV and the lowest ideality factor of 2.95 were both attained under light irradiation. In the comparison of the values of the undoped Cu/LaPO4/n-Si and Cu/Al-LaPO4/n-Si Schottky barrier diodes, the Al-LaPO4/n-Si Schottky barrier diode was found to possess a significantly better barrier height (ϕB) and ideality factor values (n) than the other. The reported results in this work are among the best to date for 10% Al-doped LaPO4 Schottky barrier diodes. Synthesis of undoped and Al doped LaPO4 NPs and fabrication of Cu/AL-LaPO4/n-Si based metal-insulator-semiconductor (MIS) Schottky barrier diodes (SBDs). [ABSTRACT FROM AUTHOR]

GaN high-electron-mobility transistors (HEMTs) have attracted widespread attention for high-power microwave applications, owing to their superior properties. However, the charge trapping effect has limitations to its performance. To study the trapping effect on the device large-signal behavior, AlGaN/GaN HEMTs and metal-insulator-semiconductor HEMTs (MIS-HEMTs) were characterized through X-parameter measurements under ultraviolet (UV) illumination. For HEMTs without passivation, the magnitude of the large-signal output wave ( X 21 FB ) and small-signal forward gain ( X 2111 S ) at fundamental frequency increased, whereas the large-signal second harmonic output wave ( X 22 FB ) decreased when the device was exposed to UV light, resulting from the photoconductive effect and suppression of buffer-related trapping. For MIS-HEMTs with SiN passivation, much higher X 21 FB and X 2111 S have been obtained compared with HEMTs. It suggests that better RF power performance can be achieved by removing the surface state. Moreover, the X-parameters of the MIS-HEMT are less dependent on UV light, since the light-induced performance enhancement is offset by excess traps in the SiN layer excited by UV light. The radio frequency (RF) power parameters and signal waveforms were further obtained based on the X-parameter model. The variation of RF current gain and distortion with light was consistent with the measurement results of X-parameters. Therefore, the trap number in the AlGaN surface, GaN buffer, and SiN layer must be minimized for a good large-signal performance of AlGaN/GaN transistors. [ABSTRACT FROM AUTHOR]

Critical process modules for the fabrication of metal–insulator–semiconductor high‐electron‐mobility transistors (MISHEMTs) based on a novel 'buffer‐free' AlGaN/GaN heterostructure grown with metal–organic chemical vapor deposition (MOCVD) are presented. The methods of isolation and passivation for this type of heterostructure are investigated. Utilizing nitrogen implantation, it is possible to achieve off‐state destructive breakdown voltages (BVs) of 2496 V for gate–drain distances up to 25 μm, whereas mesa isolation techniques limit the BV below 1284 V. The stoichiometry of the SiNx passivation layer displays a small impact on the static and dynamic on‐resistance. However, MISHEMTs with Si‐rich passivation show off‐state gate currents in the range of 1–100 μA mm−1 at voltages above 1000 V, which is reduced below 10 nA mm−1 using a stoichiometric SiNx passivation layer. Destructive BVs of 1532 and 1742 V can be achieved using gate‐integrated and source‐connected field plates for MIHEMTs with stoichiometric and Si–rich passivation layers, respectively. By decreasing the field plate lengths, it is possible to achieve BVs of 2200 V. This demonstrates the implementation of MISHEMTs with high‐voltage operation and low leakage currents on a novel "buffer‐free" heterostructure by optimizing the SiNx stoichiometry. [ABSTRACT FROM AUTHOR]

In this Letter, we demonstrated deep sub-60 mV/dec subthreshold swings (SS) independent of gate bias sweep direction in GaN-based metal–insulator–semiconductor high electron mobility transistors (MISHEMTs) with an Al0.6Ga0.4N/GaN heterostructure and in situ SiN as gate dielectric and surface passivation. Average SS values of 22 and 29 mV/dec over 3–4 orders of drain current (ID) swing were measured during forward and reverse sweeps, respectively, in a 75-nm gate length (LG) device. Sub-60 mV/dec SS was also observed in the GaN MISHEMTs with longer LG up to 350 nm. The intrinsic physical mechanisms of deep sub-60 mV/dec SS were comprehensively studied. The observed negative differential resistance in the gate current, the kinks in the output ID-VD curve, and the capacitance spike in the depletion region of the C–V curves suggest that the capture and emission of electrons in the traps are the dominant physical mechanisms responsible for the small SS. [ABSTRACT FROM AUTHOR]

Large reduction in second and third harmonic signals is measured when a sub-nanometer-to-nanometer thick insulator film is deposited over a gold substrate. Such reduction in signal reveals the spilled-out electronic states in the insulator region at the vicinity of the metal-insulator (MI) interface, which are dubbed metal insulator gap states. For metal-insulator-metal (MIM) structures, we observe electric-field enhancement saturation and quenching of the third harmonic efficiencies well above the efficiencies for MI samples. The measured harmonics of incident light scattered from the MI and MIM systems are compared with detailed simulations that account for the nonlinear interactions of free electrons spilled out into the insulator and the nonlocality and electron quantum tunneling effects. Two insulator materials (ZnO and Al2O3) are used in the experiments, and atomic layer deposition is used to cover the gold substrate with variable thickness of the insulator films. On the basis of our simulations, we conclude that the observed MIM third-harmonic signal enhancement (and quenching) effects are primarily due to the nonlocal phenomena in an electron gas. As a consequence of our findings, second- and third-harmonic scattering signals can be analyzed to extract the spill-out electron density in the insulator. [ABSTRACT FROM AUTHOR]

Metal-semiconductor-metal (MSM) architectures are popular for achieving high-responsivity Ga2O3 solar-blind photodetectors (SBPDs), however, the hot-electron-induced internal photoemission (IPE) effect restricts their detecting performance. Herein, we demonstrate the rational design of an Al/Al2O3/Ga2O3 metal–insulator-semiconductor (MIS) SBPD that has merits of enhanced responsivity, suppressed sub-gap response and ultralow dark current based on the simulation results obtained using Lumerical software. For the cylindrical patterned detectors with Al/Al2O3/Ga2O3 MIS structures, the optimized dimensions of Al electrodes with a conformed ultra-thin (2 nm) Al2O3 layer support the surface plasmon polariton resonances at 250 nm, thus improving the photoresponsivity to 74 mA W−1. Furthermore, the sandwiched Al2O3 layer lifts the barrier for hot electrons in electrodes, which significantly suppresses the IPE-induced sub-gap photoresponse by more than 105 in magnitude with respect to the Al/Ga2O3 MSM counterpart. Optical and electrical field distributions are overlapped in cylindrically patterned MIS detectors, simultaneously improving the excitation and collection efficiencies of excess carriers and resulting in the 103-boosted rejection ratio. [ABSTRACT FROM AUTHOR]

Silicon sub-bandgap near-infrared (NIR) (λ > 1100 nm) photovoltaic (PV) response by plasmon-enhanced internal photoemission was investigated. The Si sub-bandgap NIR PV response, which remains unexploited in Schottky junction-like solar cell device, was examined using nanometer sized Au/Al2O3/n-Si junction arrays. This kind of metal–insulator–semiconductor structure was similar in functionality to Schottky junction in NIR absorption, photo-induced charge separation and collection. It showed that NIR absorption increased steadily with increasing volume of Au nanoparticles (NPs) till a saturation was reached. Simulation results indicated the formation of localized surface plasmon on the surfaces of Au NPs, which was correlated well with the observed NIR absorption. On the other hand, the NIR PV response was found sensitive to the amount and size of Au NPs and thickness of Al2O3. Chemical and field-effect passivation of n-Si by using Al2O3 and SiO2 were used to optimize the NIR PV response. In the current configuration, the best PV conversion efficiency was 0.034% at λ = 1319 nm under illumination power of 0.1 W/cm2. [ABSTRACT FROM AUTHOR]

In this work, 4H-SiC lateral metal-insulator-semiconductor field-effect transistors (MISFETs) were demonstrated to operate up to 500 °C with a high on/off current ratio (over 109). A low off-state current of 3.6 × 10−9 mA/mm at 500 °C was obtained in SiC MISFET with a ring structure. The MISFETs with SiO2/SiNx/Al2O3 gate dielectric stack showed minimum subthreshold swings of 155 and 240 mV/dec at room temperature and 500 °C, respectively, indicating good thermal stability of this gate dielectric stack on SiC. An interface trap density of 1.3 × 1011 cm−2 eV−1 at E − EV = 0.2 eV was extracted from the Capacitance–Voltage (CV) measurements at room temperature, which confirms excellent dielectric interface. The electron mobility increases with increasing temperature and reaches 39.4 cm2/V s at 500 °C. These results indicate that SiC MISFETs with triple layer dielectrics and ring structure have a high potential in extreme-temperature electronics. [ABSTRACT FROM AUTHOR]

The electron-beam-induced current (EBIC) method is utilized in this work to visualize conductive channels formed in graphene oxide as a result of resistive switching. Using metal–insulator–semiconductor (MIS) structures, an increase in the electron beam induced current by a few orders of magnitude as compared with the EBIC signal in metal–insulator–metal (MIM) structures is achieved. The mechanism of the EBIC image formation related to the conductive channels is explained by the separation and collection of the e-beam generated excess carriers by rectifying barrier nanocontacts formed at the graphene oxide/Si interface during resistive switching. It is shown that the collection efficiency of the formed nanocontacts decreases with the beam energy, in agreement with the theoretical predictions for the Schottky-like nanocontacts. An important advantage of the EBIC method is demonstrated in its ability to monitor the generation and elimination of high density conductive channels even when the current–voltage measurements cannot detect and separate these processes. EBIC study of the dynamics of the conductive channel formation can help better understand the underlying physical mechanisms of their generation. [ABSTRACT FROM AUTHOR]

In this paper, we synthesized LaPO4 and In doped LaPO4 nanoparticles (NPs) with different concentrations (In-5%, 7.5%, and 10%) by the Co-precipitation method with calcined at 800 °C. The monoclinic phase with enhanced crystalline size was shown by the annealing temperature at 800 °C, which occurred in the XRD pattern. IR spectroscopy proved the presence of the phosphate group in the region of 1200 to 400 cm−1. FE-SEM images of the pure and doped higher concentrated NPs showed spherical agglomerates and dense aggregate layer structure. X-ray photoelectron spectroscopy (XPS) analysis reveals that In3+ and La3+ have a prominent appearance in the XPS study, which supports the synthesis of In-LaPO4 nanoparticles and contradicts the findings of XRD and FTIR. The optical characteristics are evaluated by UV DRS from estimated using the Kubelka Munk function, bandgap values are reduced while increasing the dopant concentration. Moreover, the fabricated metal–insulator-semiconductor (MIS) Schottky barrier diode uses In-LaPO4 NPs as an interfacial layer. The thermionic emission (TE) model determines ideality factor (n), barrier height (ϕB), and reverse saturation current (IO) are all determined from the I–V characteristics. Under light irradiation, the lowest ideality factor of 2.88, and the barrier height of 0.744 eV were achieved. [ABSTRACT FROM AUTHOR]

In this study, the reliability characteristics of metal-insulator-semiconductor (MIS) capacitor structures with low-dielectric-constant (low-k) materials have been investigated in terms of metal gate area and geometry and thickness of dielectric film effects. Two low-k materials, dense and porous low-k films, were used. Experimental results indicated that the porous low-k films had shorter breakdown times, lower Weibull slope parameters and electric field acceleration factors, and weaker thickness-dependence breakdowns compared to the dense low-k films. Additionally, a larger derivation in dielectric breakdown projection model and a single Weilbull plot of the breakdown time distributions from various areas merging was observed. This study also pointed out that the porous low-k film in the irregular-shaped metal gate MIS capacitor had a larger dielectric breakdown time than that in the square- and circle-shaped samples, which violates the trend of the sustained electric field. As a result, another breakdown mechanism exists in the irregular-shaped sample, which is required to explore in the future work. [ABSTRACT FROM AUTHOR]

In a bid to understand the commonly observed hysteresis in the threshold voltage (VTH) in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors during forward gate bias stress, we have analyzed a series of measurements on devices with no surface treatment and with two different plasma treatments before the in-situ Al2O3 deposition. The observed changes between samples were quasi-equilibrium VTH, forward bias related VTH hysteresis, and electrical response to reverse bias stress. To explain these effects, a disorder induced gap state model, combined with a discrete level donor, at the dielectric/semiconductor interface was employed. Technology Computer-Aided Design modeling demonstrated the possible differences in the interface state distributions that could give a consistent explanation for the observations. [ABSTRACT FROM AUTHOR]

Ion implantation is a key technology without alternative for doping silicon carbide SiC in the manufacturing processes of SiC devices. SiC technology has a number of distinctive features in comparison with Si-ion doping technology. This paper provides a systematic analysis of modern technical solutions aimed at the formation of local doped regions by the method of ion implantation for various purposes for SiC-based high-power electronic devices. The results of research conducted at the St. Petersburg State Electrotechnical University LETI are presented. This research is focused on the development and selection of modes of aluminum- and phosphorus-ion implantation into 4H-SiC structures that provide specified concentrations of doping impurities and geometric dimensions of local ion-doped regions. The developed ion-implantation modes are successfully implemented in the manufacture of samples of high-power 4H-SiC metal–insulator–semiconductor (MIS) transistors with operating voltages of up to 1200 V. [ABSTRACT FROM AUTHOR]

In this letter, HfO2/Al2O3/AlN hybrid stack capacitor with ferroelectric switching is experimentally demonstrated for the first time. The metal-insulator-semiconductor (MIS) capacitors and InGaZnO4 (IGZO) channel thin-film transistors (TFTs) with the HfO2/Al2O3/AlN hybrid gate stack are demonstrated in this letter. With the hybrid gate stack, the TFT exhibits the clear counter-clockwise memory windows (MWs) of 6.5 V, 6.2 V and 28.7 V respectively measured at 368 K, RT, and 80 K under the sweep voltage of ±40 V. Moreover, the retention over $10^{{4}}$ s and the endurance over $10^{{4}}$ cycles are demonstrated under the program (P)/erase (E) pulsed height of ±45 V. The results exhibit the applicable possibility of the HfO2/Al2O3/AlN stack for the high voltage memory device applications. [ABSTRACT FROM AUTHOR]

Graphene, a two-dimensional (2D) crystal consisting of one layer of carbon atoms, received intense interest in the last few decades due to its rich physics for diverse applications [[1]]. Graphene has been demonstrated as an ideal component of FGM as a floating gate, where the charge carrier from the semiconductor channel can easily be trapped in the floating gate by utilizing a tunneling barrier and a clean interface. Either the metal contact and/or the insulator layer can be transferred onto any desired target (e.g., semiconductor channel or other functional electrode, etc.), which provide the sharp interface of semiconductor/metal or semiconductor/oxide heterojunctions. In this concept, graphene has strong impacts as an electrode, which allow vertical current flows, while the bottom gate can effectively modulate the semiconductor channel via graphene due to a lower carrier concentration at the Dirac point, which can switch the device between on and off states [[10]]. [Extracted from the article]

Тhe development of a photoelectrical hydrogen sensor without sensor element heating is presented. For the sensitive element of the hydrogen sensor the Pd/n-InP (Schottkie diode) and Pd/oxide/InP (metal–insulator–semiconductor) structures were developed and investigations of the photovoltage and the photocurrent of the structures depending on the hydrogen concentration in the range 0.1–100 vol.% in a nitrogen–hydrogen gas mixture were carried out. It is shown that the photovoltage and photocurrent decay rate and the hydrogen concentration are exponentially related to each other. The laboratory samples of sensor for hydrogen determination in the range 100–30,000 ppm which are able to operate at room temperature with response rate of 1–2 s are developed. [ABSTRACT FROM AUTHOR]

A new generation of high-efficiency power devices is being developed using wide bandgap (WBG) semiconductors, like GaN and SiC, which are emerging as attractive alternatives to silicon. The recent interest in GaN has been piqued by its excellent material characteristics, including its high critical electric field, high saturation velocity, high electron mobility, and outstanding thermal stability. Therefore, the superior performance is represented by GaN-based high electron mobility transistor (HEMT) devices. They can perform at higher currents, voltages, temperatures, and frequencies, making them suitable devices for the next generation of high-efficiency power converter applications, including electric vehicles, phone chargers, renewable energy, and data centers. Thus, this review article will provide a basic overview of the various technological and scientific elements of the current GaN HEMTs technology. First, the present advancements in the GaN market and its primary application areas are briefly summarized. After that, the GaN is compared with other devices, and the GaN HEMT device's operational material properties with different heterostructures are discussed. Then, the normally-off GaN HEMT technology with their different types are considered, especially on the recessed gate metal insulator semiconductor high electron mobility transistor (MISHEMT) and p-GaN. Hereafter, this review also discusses the reliability concerns of the GaN HEMT which are caused by trap effects like a drain, gate lag, and current collapse with numerous types of degradation. Eventually, the breakdown voltage of the GaN HEMT with some challenges has been studied. [ABSTRACT FROM AUTHOR]