Optical and electrical properties of SnSe2 and SnSe thin films prepared by spray pyrolysis

Abstract Tin diselenide thin films were prepared by spray pyrolysis technique using SnCl 2 ·H 2 O and 1,1-dimethyl-2-selenourea as precursor compounds with a Se:Sn atomic ratio of 1:1 in the starting solution. The deposition process was carried out in the substrate temperature range of 275 °C to 400 °C using two solution flow rates of 5 ml/min and 8 ml/min. The phases of SnSe 2 were obtained when the deposition was carried ou at a flow rate of 5 ml/min, while for the films deposited at 8 ml/min mixed phases of SnSe 2 /SnSe were observed. Heat treatment of the deposited SnSe 2 /SnSe thin films in an atmosphere of 95% N 2 and 5% H 2 led to crystallization of the SnSe compound. The as deposited SnSe 2 thin films have an optical band gap of 1.59 eV with n-type electrical conductivity in the range of 10 − 1 (Ω cm) − 1 to 10 1 (Ω cm) − 1 . The annealed thin films have an optical band gap of 0.81 eV and show p-type electrical conductivity of 2 × 10 − 1 (Ω cm) − 1 .