Thin Solid Films, Vol.350, No.1-2, 72-78, 1999
Structure and photoconductive properties of dip-deposited SnS and SnS2 thin films and their conversion to tin dioxide by annealing in air
SnS and SnS2 thin films have been prepared by the dip technique. In this technique, a substrate was dipped into an alcoholic solution of the corresponding chloride and thiourea and then withdrawn vertically at a controlled speed, and finally baked in a high temperature furnace at atmospheric condition. XRD and SEM data suggest that good quality SnS and SnS2 films are obtained at a baking temperature of 300 and 360 degrees C, respectively. Values of band gap for SnS and SnS2 obtained from spectral response of photoconductivity are 1.4 and 1.4 eV, respectively. The indirect allowed band gap values for SnS2 film obtained from optical absorption measurements are 1.95 and 2.05 eV. Open-air annealing of both SnS and SnS2 films at 400 degrees C converts them to transparent conducting SnO2.