Characteristics of Thick m-Plane InGaN Films Grown on ZnO Substrates Using Room Temperature Epitaxial Buffer Layers

We have grown 500-nm-thick m-plane In(0.33)Ga(0.67)N films on nearly-lattice-matched ZnO substrates by the use of a GaN intermediate-layer grown at room temperature, and we have investigated their structural and optical properties. X-ray diffraction and associated reciprocal space mapping have revealed that these m-plane In(0.33)Ga(0.67)N films do not show serious phase separation, in spite of their thickness. Photoluminescence from the strained m-plane In(0.33)Ga(0.67)N was polarized with E vertical bar vertical bar c, which indicates a change in the characteristic of valence band, probably due to the large compressive strain. These properties of In(0.33)Ga(0.67)N are promising for high-efficiency solar cells and low-threshold-current laser diodes. (C) 2010 The Japan Society of Applied Physics