Photoconductivity and photoluminescence of InS monocrystals

InS single crystals grown by the Bridgmann method have concentration of current carrier concentration 7 x 1016 - 2 x 1017 cm-3, carrier mobility 8-20 cm2/V-sec, the maximum of the photoconductor spectrum at 3000K at the wavelength lambda = 0.67 μm, and the width of the forbidden band Esub(g) = 1.86 eV at 770K as determined from the photoconductor spectrum. The temperature coefficient of the forbidden band width is 10-12 x 10-4 eV/degree. The short-wavelength maximum (lambdasub(max) = 0.68 μm) of InS photoluminescence spectrum corresponds to the band-to-band transition (Esub(g) = 1.82 eV0 and the long-wavelength maximum (lambdasub(max) = 1.19 μm) is associated with recombination through an impurity level approximately 0.1 eV from the middle of the forbidden band