Electron mobility in N-polar GaN/AlGaN/GaN heterostructuress

The drift mobility of two-dimensional electron gasses in N-polar GaN/AlGaN/GaN heterostructures was measured with capacitance and resistance measurements using gated transmission line method structures. A decrease in mobility with increasing reverse bias of the gate was observed. A variational wave function was used to calculate the mobility limited by optical phonon, alloy disorder, and ionized impurity scattering as a function of gate bias, and found to match the experimental data well. Three distinct regimes where phonon, alloy, and impurity scattering are dominant were observed.