Numerical simulation of novel ultrathin barrier n-GaN/InAlN/AlN/GaN HEMT structures: Effect of indium-mole fraction, doping and layer thicknesses

The effects of thicknesses, alloy fraction and doping density of different layers in a novel pseudomorphic n-GaN/InxAl1−xN/AlN/GaN ultrathin barrier heterostructures on band structures and carrier densities were investigated with the help of one-dimensional self-consistent solutions of non-linear Schrödinger–Poisson equations. The calculations include polarization-induced carriers and thermally activated bulk carriers. Important increments in carrier density are found with increasing thickness and decreasing indium-mole fraction of InxAl1−xN ultrathin barrier layer. From an experimental point of view, two different device structures are suggested for the low-bias and high-bias applications.