The control of two-dimensional-electron-gas density and mobility in AlGaN/GaN heterostructures with Schottky gate

Abstract

The effects of Schottky gate on behavior of two-dimensional electron gas (2DEG) density and two-dimensional electron mobility (2DEM) in AlGaN/GaN heterostructures with different Al mole fraction in AlGaN barrier and its different thickness have been studied. The sheet carrier concentration, NS, was determined self-consistently from the coupled Schrödinger and Poisson equations, by assuming a real model for heterostructures and by using Numerov's method. The most dominant scattering mechanisms have been considered to calculate 2DEM with using more accurate numerical calculation and considering all intra-subband, inter-sub-band scattering. The results of our analysis clearly indicate that increasing the gate voltage leads to an increase in the 2DEG density and 2DEM. Also it shows that increasing the gate voltage for higher positive voltage; decrease the 2DE Mobility where the 2DEG density is saturated. These behaviors depend on barrier thickness and Al mole fraction.