Weak localization and magnetointersubband scattering effects in an Al_x Ga_{1 − x} N/GaN two-dimensional electron gas

Magnetotransport measurements have been carried out on a two-dimensional electron gas in a modulation-doped Al_0.22Ga_0.78N/GaN heterostructure. The weak localization and magnetointersubband scattering effects have been studied. The measurements show that the inelastic scattering time is inversely proportional to the temperature, following the prediction by weak localization theory. Furthermore, fitting the inelastic scattering time indicates an enhanced phase-breaking rate compared to the theoretical predication. At the same time, a magnetoresistance oscillation induced by intersubband scattering has also been observed. This magnetoresistance oscillation persists to a relatively high temperature in contrast to the Shubnikov-de Haas oscillation.