Energy-gap variations in semiconductor alloys

The physical origin of the bowing of energy gaps in semiconductor alloys is considered. It is shown that disorder plays no significant part in energy-gap bowing, and that the virtual crystal approximation is valid. An expression is derived for the bowing resulting from the nonlinear dependence of the crystal potential on the properties of the component ions, and very good agreement is found with experimental data for sixteen alloys at the Gamma point ad eight alloys at the L point.