Effects of Pressure on the Electronic and Optical Properties of a Polymorph of Germanium and of Amorphous Germanium

Abstract

It has been observed experimentally that the density dependence of the energy gap of a tetrahedrally coordinated amorphous semiconductor is generally smaller than that of its crystalline form. Using the Ge 3 or ST12 structure as a simple model of amorphous Ge ($a-\mathrm{G}\mathrm{e}$), the electronic structure of this simple model of $a-\mathrm{G}\mathrm{e}$, calculated using the pseudopotential method, is obtained at several densities. The resulting density dependence is found to be small.