Softening of elastic moduli of amorphous semiconductors

Abstract

We study the rigidity problem of amorphous semiconductors using Monte Carlo (MC) simulations and empirical potentials. We find that networks of tetrahedral a-C, a-Si, and a-Ge consistently have smaller elastic moduli than their crystalline counterparts. The reduction of rigidity seems to be associated with the reduced density and the random orientation of sp 3 hybrids in the fully tetrahedral amorphous networks and, in addition, with the presence of sp 2 sites in tetrahedral a-C.