The cooling effect on structural, electrical, and optical properties of epitaxial a-plane ZnO:Al on r-plane sapphire grown by pulsed laser deposition

Abstract

Here, the unambiguous effect of cooling rate on structural, electrical, and optical properties of a-plane ZnO:Al on r-plane sapphire grown by pulsed laser deposition at 700 degrees C is reported. A high cooling rate (similar to 100 degrees C/min) can result in stripe morphology along m-direction and significant deformation on the epitaxial films of a-plane ZnO:Al with deteriorated crystallinity and significantly lowered resistivity. Also, photoluminescence spectra exhibit high intensities of excess violet and green emissions with low intensity of near band edge luminescence. Comparison with pure a-plane ZnO films is also presented. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759032]