Raman study of alloy potential fluctuations in Mg(x)Zn(1-x)O nanopowders.

The blueshift of near-band-edge emission and excitonic absorption indicate that Zn(2+) ions are successfully substituted by Mg(2+) ions in Mg(x)Zn(1-x)O nanopowders for 0≤x≤0.14. The changes in Raman spectral linewidth and the asymmetry of the E(2) (high) mode for various Mg contents can be well described by a modified spatial correlation model that considers the grain size distribution. With increasing Mg concentration, the alloy potential fluctuations lead to a decrease in the grain size, which is induced by the surplus Mg(2+) that could form MgO clusters surrounding the crystalline MgZnO.