Structural and Optical Properties of Nonpolar AlN(1120) Films Grown on ZnO(1120) Substrates with a Room-Temperature GaN Buffer Layer

Abstract

We have grown a-plane AlN films on ZnO substrates using room temperature epitaxial GaN buffer layers by pulsed laser deposition (PLD). The basal plane stacking fault density of these AlN(1120) films, as estimated from X-ray rocking curve measurements, is as low as 1.1×105 cm-1, which is attributed to the use of ZnO substrates with a small lattice mismatch. Cathode luminescence spectra measured at 300 K exhibited a clear near band-edge peak of AlN at around 5.9 eV. The use of a PLD low-temperature growth technique and ZnO substrates would be quite attractive for the fabrication of ultraviolet light-emitting devices.