INFLUENCE OF SULPHUR MOLAR CONCENTRATION ON STRUCTURAL AND OPTICAL PROPERTIES OF TIN SULPHIDE TIN FILMS

The sulphur concentration plays an important role on the stoichiometry of sulphur based thin films due to its volatility. In the present work tin sulphide (SnS) thin film have been prepared by ultrasonic spray pyrolysis method on glass substrates. In order to optimize the sulphur molarity, it was varied in the range 0.01 to 0.09M in the starting solution, while the other deposition parameters are maintained constant. The films structural and optical properties were studied as a function of the molar concentration of sulphur. The results indicated that tin sulphide films grown at low molar concentration exhibit a single phase of SnS orthorhombic structure increasing the sulphur molar concentration above 0.07M is accompanied by the emergence of Sn2S3 secondary phase. The film thickness and average of films crystallite size value increases the sulphur concentration. We inferred that 0.07 M is the optimal condition leading to film sitable for solar cell production.