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In this paper, the performance of silicon carbide (SiC) light-triggered thyristor (LTT) with a p-type NiO emitter region is analyzed through numerical simulation. The conductivity modulation in SiC LTT is significantly enhanced with the help of high injection efficiency of holes in NiO/SiC heterojunction. The injected hole density at the surface of the p− long base is increased by ∼21.2 times and the corresponding specific on-state resistance (Ron,sp) is only 36.7 mΩ cm2, which is reduced by about 29%. Moreover, hole-injection enhancement by NiO/SiC heterojunction also exhibits excellent potential in improving the dynamic characteristics of SiC LTTs. The simulation results indicate that the turn-on time of SiC LTT can be reduced by ∼57.76% when triggered by 1.0 W/cm2 ultraviolet light. Furthermore, energy dissipations of SiC LTT during the turn-on and turn-off processes can be reduced by 91.4% and 21.9%, respectively.

The influence of frequency characteristics of devices is complex. The effects of AlN barrier thickness, gate length, gate-drain spacing and work function on the frequency characteristics of AlN/ β-Ga2O3 high electron mobility transistor (HEMT) were studied by Sentaurus TCAD in this paper. The following conclusions are obtained: as the thickness of the AlN barrier layer increases from 10 nm to 25 nm, the cutoff frequency (fT) and maximum oscillation frequency (fmax ) rise by 18 and 17 GHz respectively. The decrease of gate capacitance is the main reason for the increase of fT . Furthermore, it was found that the thinner barrier layer enhanced the gate's ability to control the channel electrons. When the gate length is scaled down from 0. 9 μm to 0. 1 μm, fT and fmax increase by 84 and 98 GHz, respectively, representing a far more profound influence on frequency characteristics than the barrier layer thickness. However, when the gate length fell below 0. 1 μm, short-channel effects emerged. As the gate-drain spacing increase, fT exhibits a slight decrease. Coupled with the concurrent reduction in source resistance, this led to a synchronized trend in fmax and fT only when the gate-source voltage (VGS ) exceeds - 1. 2 V. The work function, on the other hand, has minimal impacts on fT and fmax, but an increase in the work function positively influenced the device' s pinch-off characteristics. In summary, this paper indicates that by shortening the gate length while concurrently augmenting the thickness of the AlN barrier layer, gate-drain spacing, and work function, one can enhance the frequency characteristics while also improving the pinch-off characteristics of the device, which has certain guiding significance for the design of HEMT devices. [ABSTRACT FROM AUTHOR]

The epitaxial growth of high‐quality and large‐area monolayer (ML) MoS2 has attracted widespread attention in recent years. Here, MoS2 on Al2O3 substrate was prepared by using atmospheric‐pressure chemical vapor deposition. The process parameters such as temperature difference and distance between MoO3 and Al2O3, nucleation temperature, and heating rate were optimized. The high MoO3 evaporation temperature facilitates Mo vapor transport to grow ML‐MoS2. The introduction of nucleation temperature facilitates the deposition of MoS2, and the morphology of the nucleation point is related to the amount of MoO3‐x deposited on Al2O3. This process optimization method is also applicable to growth MoS2 on SiO2. The ML‐MoS2 with a size greater than 1 cm2 was successfully fabricated on Al2O3 and SiO2, which laid a foundation for the practical application of ML‐MoS2. [ABSTRACT FROM AUTHOR]

To date, research on defect-induced magnetism in SiC has been conducted to clarify the relationship between the ferromagnetic signal and the carrier concentration. It has been experimentally proven that there is an interaction between the d 0 magnetic moment and the hole carrier in p-type 4H-SiC. However, for n-type SiC, the existing theoretical predictions are insufficient to explain the variation in magnetization with the doping concentration. To solve this problem, we prepared 4H-SiC epitaxial layers with different nitrogen doping concentrations and introduced defects by ion implantation. By measuring and analyzing the magnetic properties, we found that the ferromagnetic composition depends on both the implantation dose and the doping concentration. By performing first-principles calculations, we studied the magnetic moments and interactions of defects with different charge states, which is related to defect-induced ferromagnetism. These defects include not only the paramagnetic centers reported in previous studies, such as silicon vacancies and divacancies, but also the N C V Si complex defect of recent interest, which are indicated by positron annihilation experiments. Combining experimental observations with theoretical calculations, we explained the relationship between magnetic properties and the nitrogen doping concentration in the epitaxial samples. Our research will help us to better understand the physical mechanism of defect-induced magnetism in doped semiconductors and provide a potential platform for the control of defect-induced magnetism by carrier density modulation and the fabrication of SiC spintronic devices without transition metals. [ABSTRACT FROM AUTHOR]