Effects of magnesium contents in ZnMgO ternary alloys grown by molecular beam epitaxy

Abstract

Ternary alloys of ZnMgO samples with different magnesium contents have been grown by molecular beam epitaxy on the sapphire substrates. Room temperature photoluminescence energy of ZnMgO shifted as high as 3.677 eV by increasing Mg contents corresponding to the higher Urbach average localization energy which indicates more randomness in the alloys with higher Mg contents. XRD results are also verified that the c-axis length decreases as the increasing Mg contents linking to the increased tensile stress produced by the Mg atoms. Raman spectra analyzed by the spatial correlation model to describe that the linewidth Gamma is decreased but the correlation length L is increased as the increasing of Mg contents. (C) 2015 Elsevier B.V. All rights reserved.