Optical properties of a ‘quasi-disordered’ semiconductor: ZnIn2S4

Optical absorption and thermoluminescence measurements have been performed on single crystals of ZnIn₂S₄. An absorption edge and a distribution of traps which depend exponentially on the radiation energy with the same ‘slope’, have been found. These results provide evidence for the existence of a considerable amount of intrinsic disorder in this compound, and allow one to relate the discussion to the wider problem of the optical properties of amorphous semiconductors.