Electron mobility in Al_xGa_1-xN/GaN heterostructures

Theoretical electron mobility limits of a two-dimensional electron gas (2DEG) confined near the interface of a Al_xGa_1-xN/GaN heterostructure are computed. The electronic structure of the 2DEG is calculated self-consistently to obtain the best analytic solution for the wave functions, and the results are used to compute the mobilities. All standard scattering mechanisms, including scattering by acoustic and optical phonons, remote and background impurities, and alloy disorder have been included in our calculations. Depending on the exact composition of the heterostructure, the low-temperature mobility may be limited by either Coulomb or alloy disorder scattering. Strategies for optimizing the mobility for various remote doping concentrations and spacer widths are discussed. Intrinsic mobilities in excess of 10⁶cm²/V s are predicted for optimized heterostructures at low temperatures.