ELECTRICAL AND OPTICAL BEHAVIOR OF VAPOR-GROWN SNS2 CRYSTALS

Single-crystal groth of tin disulphide using chemical vapour (iodine) transport has been reported. The electrical resistivity, Hall mobilit y and optical absorption of the vapour-grown crystals have been invest igated. The grown crystals show three different regions characterized by different operating conduction mechanisms. The electrical behaviour of the physical vapour-grown crystals in the 77-300 K temperature ran ge reveals that the material can be obtained as a classical or a degen erate semiconductor depending upon the zone temperature interval. The optical absorption spectra in the 450-800 nm wavelength range has been analysed thoroughly to obtain direct and indirect allowed and forbidd en transitions. An indirect transition assisted by phonon energy 0.04 eV has been identified in these crystals.