Local structure evolution in polycrystalline Zn${}_{1-x}$Mg${}_x$O ($0\le x\le 0.15$) studied by Raman and by synchrotron x-ray pair distribution analysis

Abstract

The local structures of Zn${}_{1-x}$Mg${}_x$O alloys have been studied by Raman spectroscopy and by synchrotron x-ray pair distribution function (PDF) analysis. Within the solid solution range ($0\le x\le 0.15$) of Zn${}_{1-x}$Mg${}_x$O, the wurtzite framework is maintained with Mg homogeneously distributed throughout the wurtzite lattice. The $E_2^{\mathrm{high}}$ Raman line of Zn${}_{1-x}$Mg${}_x$O displays systematic changes in response to the evolution of the crystal lattice upon the Mg-substitution. The red-shift and broadening of the $E_2^{\mathrm{high}}$ mode are explained by the expansion of hexagonal $ab$-dimensions, and compositional disorder of Zn/Mg, respectively. Synchrotron x-ray PDF analyses of Zn${}_{1-x}$Mg${}_x$O reveal that the Mg atoms have a slightly reduced wurtzite parameter $u$ and more regular tetrahedral bond distances than the Zn atoms. For both Zn and Mg, the internal tetrahedral geometries are independent of the alloy composition.

10 pages, 12 figures RevTex

Cited by in corpus (1)

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