Raman Scattering, Thermal studies and Reverse Monte Carlo Simulations of an Amorphous Ge${}_{30}$Se${}_{70}$ Alloy Produced by Mechanical Alloying

Abstract

The short and intermediate range order of an amorphous Ge${}_{30}$Se${}_{70}$ alloy produced by Mechanical Alloying were studied by Reverse Monte Carlo simulations of its x-ray total structure factor, Raman scattering and differential scanning calorimetry. The simulations were used to compute the $G_{\text{Ge-Ge}}^{\text{RMC}}(r)$, $G_{\text{Ge-Se}}^{\text{RMC}}(r)$ and $G_{\text{Se-Se}}^{\text{RMC}}(r)$ partial distribution functions and the ${\mathcal{S}}_{\text{Ge-Ge}}^{\text{RMC}}(K)$, ${\mathcal{S}}_{\text{Ge-Se}}^{\text{RMC}}(K)$ and ${\mathcal{S}}_{\text{Se-Se}}^{\text{RMC}}(K)$ partial structure factors. We calculated the coordination numbers and interatomic distances for the first and second neighbors and the bond-angle distribution functions ${\Theta }_{ijl}(\cos \theta )$. The data obtained indicate that the structure of the alloy has important differences when compared to alloys prepared by other techniques. There are a high number of Se-Se pairs in the first shell, and some of the tetrahedral units formed seemed to be connected by Se-Se bridges.

8 pages, 8 figures, submitted to J Chem Phys