Electron Transport Characteristics of Wurtzite GaN

A three-valley Monte Carlo simulation approach was used to investigate electron transport in wurtzite GaN such as the drift velocity, the drift mobility, the average electron energy, energy relaxation time, and momentum relaxation time at high electric fields. The simulation accounted for polar optical phonon, acoustic phonon, piezoelectric, intervalley scattering, and Ridley charged impurity scattering model. For the steady-state transport, the drift velocity against electric field showed a negative differential resistance of a peak value of ？m/s at a critical electric field strength ？V/m. The electron drift velocity relaxes to the saturation value of ？m/s at very high electric fields. The electron velocities against time over wide range of electric fields are reported. 1. Introduction In recent years, nearly all electronic and optoelectronic devices have been realized using alloys of the III–V nitrides, gallium nitride (GaN), aluminum nitride (AlN), and indium nitride (InN) [1, 2]. There has been considerable interest in GaN due to its wide band gap and favorable material properties, such as high electron mobility and very high thermal conductivity [3]; GaN and related compounds with aluminum and indium currently have great potential for applications in optoelectronics devices in the frequency range from microwaves to ultraviolet, quantum dots infrared photodetectors [4–7]. GaN also has large speed electron velocity and can be used for electronics devices [8]. The electron transport characteristics of the III–V nitride semiconductor, GaN, have long been recognized. In 1975, Littlejohn et al. [9] were the first to report results obtained from semiclassical Monte Carlo simulations of the steady-state electron transport within bulk wurtzite GaN. In 1993, Gelmont et al. [10] reported on ensemble semi-classical two-valley Monte Carlo simulations of the electron transport within bulk wurtzite GaN; this analysis improvs upon the analysis of Littlejohn et al. [9], by incorporating intervalley scattering into the simulations. In 1995, Mansour et al. [11] reported the use of such an approach in order to determine how the crystal temperature influences the velocity-field characteristic associated with bulk wurtzite GaN. Kolnik et al. [12] reported on employing full-band Monte Carlo simulations of the electron transport within bulk wurtzite GaN and bulk zinc-blende GaN. In 1998, Albrecht et al. [13] reported on employing ensemble semiclassical five-valley Monte Carlo simulations of the electron transport within bulk wurtzite GaN, with the aim of determining