The effect, of excess CdS in CdGa2S4, upon the spectrum of defect states in its band-gap was investigated. Comparative investigations were made of the Raman, photoluminescence and cathodoluminescence spectra; as well as of the kinetics of photoconductivity in normal crystals (type A) and in crystals obtained under excess CdS conditions (type B). It was found that the main types of defect in type-A crystals were Cd and S vacancies, antisite GaCd donor defects; as well as IS defects which were caused by the incorporation of carrier gas. In type-B crystals, besides IS, the main defects were antisite acceptor defects, CdGa, as well as interstitial atoms, Cdi and Si. It was demonstrated that the emission characteristics of the crystals were determined by associations of the above defects. A luminescence band which peaked at 0.971eV was observed for the first time. This band was related to intra-center transitions in the d-shell of the Cd in the CdGa defect; which was split due to the effects of the crystalline field and spin–orbit interaction in the presence of Si.

The Effect of Composition on the Properties and Defect Structure of the CdS–Ga2S3 Solid Solution. E.F.Venger, I.B.Ermolovich, V.V.Milenin, V.P.Papusha: Semiconductors, 2002, 36[7], 763-71