Some physical properties of chalcopyrite and orthorhombic AgInS2 thin films prepared by spray pyrolysis

AgInS2 thin films were prepared by spray pyrolysis of an alcoholic solution of silver acetate, indium chloride and thiourea. The samples were grown at substrate temperatures of 375 and 400 °C from a spray solution in which the silver to indium molar ratio ([Ag]/[In]) was varied in the range 0.5–1.625. The AgInS2 chalcopyrite phase and its orthorhombic modification were found to be predominant ones in the films grown from solutions with [Ag]/[In]=0.87–1.6 and 0.87, respectively. The Ag2S, In2S3 and AgIn5S8 secondary phases were found to present in sprayed films. Estimated optical gap energies were 1.88 and 2.03 eV for chalcopyrite AgInS2 and 1.98 eV for orthorhombic AgInS2. All deposited films exhibited n-type conduction and a room temperature resistivity in the range 103–106 Ω m.