Temperature dependence of the band gap of AgIn7S11 single crystals

AgIn7S11 single crystals are herein grown by the vertical Bridgman method. The composition of the obtained single crystals is determined by X-ray microprobe analysis as well as the crystal structure – by X-ray diffraction analysis. It is shown that the obtained single crystals are crystallized in the cubic spinel structure. Using transmission spectra in the tem- perature range 10–320 K we determined the band gap of these single crystals and plotted its temperature dependence. This dependence is similar to that of the majority of semiconductor materials, namely, Eg increases with decreasing the tempera- ture. We showed the agreement of the calculated and experimental values.