Photoluminescence and photocurrent studies of p-type GaN with various thermal treatments

摘要

We present a photoluminescence and photocurrent study of the Mg-doped p -type GaN grown on sapphire substrate by metalorganic chemical vapor deposition. In photoluminescence spectra, ether a strong blue emission at 2.88 eV or weak band-edge-related photoluminescence peaks were observed at room temperature, depending on the initial condition of annealing. The photocurrent spectra exhibit a main band located at 3.0 eV, and an additional band around 1.22 eV depending also on the annealing condition. The photoluminescence and photocurrent results suggest that the photocurrent peak at 1.22 eV is associated with the absorption from the valence band edge to the deep donor state located above the Mg acceptor level.