Experimental study of the anode injection efficiency reduction of 3.3-kV-class NPT-IGBTs due to backside processes

The anode injection efficiency reduction of 3.3-kV-class non-punch-through insulated-gate bipolar transistors （NPT-IGBTs） due to backside processes is experimentally studied through comparing the forward blocking capabilities of the experiments and the theoretical breakdown model in this paper.Wafer lifetimes are measured by aμ-PCD method,and well designed NPT-IGBTs with a final wafer thickness of 500μm are fabricated.The test results show higher breakdown voltages than the theoretical breakdown model in which anode injection efficiency reduction is not considered.This indicates that anode injection efficiency reduction must be considered in the breakdown model.Furthermore,the parameters related to anode injection efficiency reduction are estimated according to the experimental data.

Simulation study of blue InGaN multiple quantum well light-emitting diodes with different hole injection layers

InGaN-based light-emitting diodes with p-GaN and p-A1GaN hole injection layers are numerically studied using the APSYS simulation software. The simulation results indicate that light-emitting diodes with p-A1GaN hole injection layers show superior optical and electrical performance, such as an increase in light output power, a reduction in current leakage and alleviation of efficiency droop. These improvements can be attributed to the p-A1GaN serving as hole injection layers, which can alleviate the band bending induced by the polarization field, thereby improving both the hole injection efficiency and the electron blocking efficiency.

A new method for evaluating the injection effect of chemical flooding

Hall plot analysis,as a widespread injection evaluation method,however,often fails to achieve the desired result because of the inconspicuous change of the curve shape.Based on the cumulative injection volume,injection rate,and the injection pressure,this paper establishes a new method using the ratio of the pressure to the injection rate（RPI） and the rate of change of the RPI to evaluate the injection efficiency of chemical flooding.The relationship between the RPI and the apparent resistance factor（apparent residual resistance factor） is obtained,similarly to the relationship between the rate of change of the RPI and the resistance factor.In order to estimate a thief zone in a reservoir,the influence of chemical crossflow on the rate of change of the RPI is analyzed.The new method has been applied successfully in the western part of the Gudong 7th reservoir.Compared with the Hall plot analysis,it is more accurate in real-time injection data interpretation and crossflow estimation.Specially,the rate of change of the RPI could be particularly suitably applied for new wells or converted wells lacking early water flooding history.

A molecular cobaloxime cocatalyst and ultrathin FeOOH nanolayers co-modifiedBiVO_(4) photoanode for efficient photoelectrochemical water oxidation

BiVO_(4) has been attracting a lot of interest in photoelectrochemical (PEC) water oxidation due to its efficient solar absorption and appropriate band positions.So far,sluggish water oxidation kinetics and fast photogenerated charge recombination still hinder the PEC performance ofBiVO_(4) .In this study,a novel PEC photoanode was designed by depositing ultrathin FeOOH nanolayers on the surface of nanoporousBiVO_(4) electrode,followed by modification with a cobaloxime (Co(dmgH)_(2)(4-COOH-py)Cl) molecular cocatalyst.Under irradiation of a 100 mW cm^(-2)(AM 1.5G) Xe lamp,the photocurrent density of the cobaloxime/FeOOH/BiVO_(4) composite photoanode reached 5.1 mA cm^(-2)at 1.23 V vs.RHE in 1.0 M potassium borate buffer solution (pH=9.0).The onset potential of the optimal cobaloxime/FeOOH/BiVO_(4) photoanode exhibited a 460 m V cathodic shift relative to bareBiVO_(4) .In addition,the surface charge injection efficiency of the composite photoanode reached~80%at 1.23 V vs.RHE and the incident photon-to-current efficiency (IPCE) reached~88%at 420 nm.

Analysis of Power Distribution on Beamline Components at Different Neutralization Efficiencies on NBI Test Stand

Neutral beam injection is recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, two sets of neutral beam injector（4–8 MW, 10–100 s） were built and operated in 2014. Neutralization efficiency is one of the important parameters for neutral beam. High neutralization efficiency can not only improve injection power at the same beam energy, but also decrease the power deposited on the heat-load components in the neutral beam injector（NBI）. This research explores the power deposition distribution at different neutralization efficiencies on the beamline components of the NBI device. This work has great significance for guiding the operation of EAST-NBI, especially in long pulse and high power operation, which can reduce the risk of thermal damage of the beamline components and extend the working life of the NBI device.

High performance of hot-carrier generation,transport and injection in TiN/TiO_(2)junction

Improving the performance of generation,transport and injection of hot carriers within metal/semiconductor junctions is critical for promoting the hot-carrier applications.However,the conversion efficiency of hot carriers in the commonly used noble metals(e.g.,Au)is extremely low.Herein,through a systematic study by first-principles calculation and Monte Carlo simulation,we show that TiN might be a promising plasmonic material for high-efficiency hot-carrier applications.Compared with Au,TiN shows obvious advantages in the generation(high density of low-energy hot electrons)and transport(long lifetime and mean free path)of hot carriers.We further performed a device-oriented study,which reveals that high hotcarrier injection efficiency can be achieved in core/shell cylindrical TiN/TiO_(2)junctions.Our findings provide a deep insight into the intrinsic processes of hot-carrier generation,transport and injection,which is helpful for the development of hot-carrier devices and applications.