Alloy composition and optoelectronic properties of dilute GaSb1−xNx by pseudo-potential calculations

We present a theoretical study of the electronic structure and optical properties of zinc-blende GaSb1−xNx semiconducting dilute alloys for small amounts of N (0⩽x⩽0.05). Our calculations are based on the pseudo-potential scheme within the virtual crystal approximation that takes into consideration the effects of compositional disorder. In agreement with previous studies, it is found that the introduction of only a few percent of N into GaSb reduces substantially the energy band gaps. It is shown that GaSb1−xNx can be a direct or an indirect semiconductor depending on the N content. Negative band gaps in the material of interest are predicted to occur when the N concentration exceeds 0.026. The information derived from the present study shows that GaSb1−xNx (0⩽x⩽0.017) should enable access to wavelengths in the 2–4 μm range.