FREE-ENERGY MODEL FOR BONDING IN A-SI ALLOYS

A free energy model (FEM) for predicting the bonding in amorphous covalent alloys has been developed and applied to alloys of a-Si. The bonds favored by chemical ordering (CO) and their relative concentrations have been determined by minimizing the Gibbs free energy of mixing G(M) = H(M) - TS(M) of the alloys, where H(M) and S(M) are the enthalpy and entropy of mixing, respectively. Predictions of the FEM will be given for the a-SiwNx, a-SiwNxHz, a-SiwOyHz, a-SiwNxOyHz, a-SixCy, and a-SixCyHz alloy systems. The bonds favored by CO in these alloys will be identified.