Reverse monte carlo simulations,raman scattering,and thermal studies of an amorphous Ge_(30)Se_(70) alloy produced by mechanical alloying

摘要

The short-and intermediate-range orders of 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_(Ge-Ge)~(RMC)(r),G_(Ge-Se)~(RMC)(r),and G_(Se-Se)~(RMC)(r) partial distribution functions and the S_(Ge-Ge)~(RMC)(K),S_(Ge-Se)~(RMC)(K),and S_(Se-Se)~(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.