Ultraviolet optical properties analysis of wurtzite AlN films grown by vapor phase epitaxy

Abstract The UV optical properties of (0 0 2) AlN thin films were studied. Under the excitation of 213 nm laser, there are two emission peaks of AlN in UV-A band with thermal quenching phenomenon. Combined with variable temperature Raman experiment, it is proved that the UV emission of AlN is accompanied by a nonradiative transition in the form of lattice thermal vibration. Density functional theory (DFT) calculations show that donor and acceptor levels can be introduced near the conduction band minimum (CBM)and near the valence band maximum (VBM) by the nitrogen vacancy, respectively. Combined with the annealing experiment, it is proved that the nitrogen vacancy (VN) is the main reason for the ultraviolet luminescence of AlN films. These results are highly relevant for a better understanding of the study of the application of AlN based materials in ultraviolet optical devices.