A Transport Study of AlGaN/GaN Heterostructures Grown on an AlN Substrate

AlGaN/GaN heterostructures grown on AlN substrates by MOCVD/MEMOCVD technique were investigated using Hall and magnetoresistance measurements. The results indicate the presence of well defined Shubnikov-de Haas (SdH) oscillations which confirm the presence of a good quality two-dimensional electron gas in this structure. The carrier density and mobility were roughly 1.19x10$^{13}$ cm$^{-2}$ and 1100 cm$^{2}$/Vs at room temperature and 1.02x10$^{13}$ cm$^{-2}$ and 5279 cm$^{2}$/Vs at 10 K, respectively. Following illumination, a persistent photocurrent and an increase in the SdH amplitude were observed. Both of these effects are indicative of an increase in the quantum scattering time. The value of the ratio of the classical to the quantum scattering times is within the expected values for the AlGaN/GaN grown on other substrates.