In this study, we proposed β-Ga₂O₃ JFET using nitrogen doping and analyzed the electrical characteristics. In β-Ga₂O₃, nitrogen ions act as a deep acceptor and are used to implement the current blocking layer. By using this characteristic of the nitrogen ion, in the proposed JFET, nitrogen ions are used to obtain gate control and pinch off the channel of the JFET. The numerical TCAD simulation was performed to design and analyze the proposed JFET. The simulated forward and reverse characteristics of the proposed JFET were obtained as a function of JFET width and nitrogen doping concentration. The maximum breakdown voltage of 1.7 kV was obtained with the on-resistance of 16.7 mΩ·cm² when the channel width was 1.5 μm and nitrogen doping concentration is 1×1018/cm³, respectively.

Nitrogen-doped graphene was synthesized by a hydrothermal method using graphene oxide (GO) as the raw material, urea as the reducing agent and nitrogen as the dopant. The morphology, structure, composition and electrochemical properties of the samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorptiondesorption analysis, electrical conductivity and electrochemical tests. The results show that urea can effectively reduce GO and achieve nitrogen doping under the hydrothermal conditions. By adjusting the mass ratio of raw materials to dopants, the graphene with different nitrogen doping contents can be obtained; the nitrogen content range is from 5.28~6.08% (atomic fraction percentage).When the ratio of dopant to urea is 1:30, the nitrogen doping content reaches a maximum of 6.08%.The supercapacitor performance test shows that the nitrogen content prepared by the ratio of 6.08% is the best at 0.1 A·g^-1. The specific capacitance is 95.2 F·g^-1.

We analyzed the correlation between breakdown voltage(BDV) of liquid nitrogen(LN2) and factors. The chosen factors affecting the breakdown are the diameter of electrode, gap length, temperature of LN2, and pressure of LN2. The BDV of LN2 was increased with increasing the diameter, the gap length and the pressure. And The BDV of LN2 was increased with decreasing the temperature. However, correlation coefficient was different from each other depending on the situation. The BDV exhibited a very high correlation coefficient of 0.92227 to dependence on the diameter. And a very high correlation coefficient of 0.94980 to dependence on the pressure under sphere(D 7.5 mm)-plane electrode. When the pressure is applied, sphere-plane electrode is the correlation coefficient was higher than that of the needle-plane electrode. It shows the dependence of a temperature coefficient of ?0.758290 ~ -0.39946 under needle-plane electrode.

In this paper, we study the insulating properties of the liquid nitrogen(LN2) including the thermal bubbles. The shape of the thermal bubbles in accordance with the current change was observed in the 77 K and 65 K LN2. According to the temperature of liquid nitrogen, bubbles were generated differently. The round shape of the bubble is occurred in 77 K LN2. But the layer shape of bubble is occurred in 65 K LN2. When the bubbles present, the dielectric strength of liquid nitrogen is low. However, the breakdown patterns were different according to the electrode arrangement. AC breakdown voltage(BDV) was lower than the DC BDV due to the influence of bubbles. Therefore, the design of a high-voltage superconducting equipments should consider the bubbles.

For feasible study of opto-electrical application regarding to oxide semiconductor, weimplemented the N doped ZnO growth using a atomic layer deposition technique. The p-type ZnOdeposition, necessary for ZnO-based optoelectronics, has considered to be very difficulty due tosufficiently deep acceptor location and self-compensating process on doping. Various sources of N such asN2, NH3, NO, and NO2 and deposition techniques have been used to fabricate p-type ZnO. Hallmeasurement showed that p-type ZnO was prepared in condition with low deposition temperature anddopant concentration. From the evaluation of photoluminescence spectroscopy, we could observe defectformation formed by N dopant. In this paper, we exhibited the electrical and optical properties of N-dopedZnO thin films grown by atomic layer deposition with NH3OH doping source.