Electron transport property in wurtzite GaN at high electric field with Monte Carlo simulation

Abstract

We present the results of the electron transport property in wurtize GaN using an ensemble full band Monte Carlo simulation. The data of wurtzite GaN band structure calculated with the first-principles total-energy pseudopotential method is used in the simulations. The impact ionization scattering rate is calculated based on Cartier’s method. The average electron drift velocity and the average electron energy each as a function of electric field are computed. The electron impact ionization coefficient is calculated as a function of applied electric field. The analysis of the impact ionization coefficient shows that when the applied electric field is greater than 1 MV/cm, the obvious impact ionization events occur. The analysis of the quantum yield shows that when the electron energy is greater than 7 eV, the quantum yield increases rapidly with electron energy increasing. We study the occupancy of the electrons in the eight conduction bands at the applied electric field ranging from 0 to 4 MV / cm. For the case of the low applied electric field all of the electrons are located in the 1st conduction band. With the increase of the applied electric field, some of the electrons move to high index conduction bands. For the whole range of the applied electric field, most of the electrons are located in the 1st conduction band and 2nd conduction band, a small number of the electrons are located in the 3rd, 4th and 5th conduction band, and very few electrons are located in the 7th and 8th conduction band.