Formation of intermediate band in ZnTe: O highly mismatched alloy synthesized by ion implantation

ZnTe:O highly mismatched alloys have been produced by isoelectric oxygen implantation into ZnTe and the micro structural and optical properties of ZnTe:O materials have been investigated in detail. The proper dose of oxygen ions led to the formation of intermediate band located at the energy level of ~0.45eV below the conduction band while high dose of oxygen ions caused an amorphous ZnTe surface layer and enhanced the deep level emission around 1.6eV. The results suggest that the reduction of lattice disorder is needed to convert localized states of intermediate band into extended states, which is crucial to realize high efficiency ZnTe:O based intermediate band solar cells.