Preparation and characterisation of sprayed tin sulphide films grown at different precursor concentrations

Tin sulphide films have been grown by spray pyrolysis technique at different precursor concentrations varied in the range, 0.01–0.2 M keeping other deposition parameters constant. The physical properties of the deposited films were systematically studied in relation to the precursor concentration. The studies indicated that the films grown in the precursor concentration range, 0.09–0.13 M were nearly stoichiometric with the Sn, S ratio of 1.06 and exhibited only SnS phase with a strong (1 1 1) preferred orientation that belongs to the orthorhombic crystal structure. These single-phase films showed an average electrical resistivity of 32.9 Ω cm, Hall mobility of 139 cm2 V−1 s−1 and carrier density of ∼1015 cm−3. These films had an average optical band gap of 1.32 eV with an absorption coefficient greater than 104 cm−1. These properties demonstrated that single-phase SnS films could be used as an absorber layer in the fabrication of heterojunction solar cells.