Magnetotransport, optical, and electronic subband properties in AlxGa1-xN/AlN/GaN heterostructures

Abstract

The Shubnikov-de Haas (S-dH) results at 1.5 K for AlxGa1-xN/AlN/GaN heterostructures and the fast Fourier transformation data for the S-dH data indicated the occupation by a two-dimensional electron gas (2DEG) of one subband in the GaN active layer. Photoluminescence (PL) spectra showed a broad PL emission about 30 meV below the GaN exciton emission peak at 3.474 eV that could be attributed to recombination between the 2DEG occupying in the AlN/GaN heterointerface and photoexcited holes. A possible subband structure was calculated by a self-consistent method taking into account the spontaneous and piezoelectric polarizations, and one subband was occupied by 2DEG below the Fermi level, which was in reasonable agreement with the S-dH results. These results can help improve understanding of magnetotransport, optical, and electronic subband properties in AlxGa1-xAs/AlN/GaN heterostructures. (C) 2004 Elsevier Ltd. All rights reserved.