Effect of Fermi Level Motion on ESR and Optical Properties of CuAlS2

摘要: Optical absorption and electron spin resonance (ESR) spectra have been studied in as-grown, Cr-doped, annealed different atmospheres CuAlS2 crystals. It has found that the major influence on optical ESR properties of crystals, obtained by chemical vapour transport, arises from transition ions Fe3+ Cr2+, which are present crystal lattice as residual impurities. Thermal treated crystals exhibit drastic changes their depending annealing atmosphere, is explained process Fermi level motion vicinity Fe2+/Fe3+ Cr+/Cr2+ demarcation levels. The results show valence states Fe Cr relative amounts each state controlled position band gap host crystal, stoichiometry dependent.