Bath Temperature Effects on the Microstructural and Morphological Properties of SnS Thin Films

Tin sulphide (SnS) thin films are synthesized by cathodic electodeposition onto indium doped tin oxide coated conducting glass substrates at various bath temperatures from 30 to 90 °C. Film thickness is estimated in the range between 640 nm and 850 nm using surface profilometer. X-ray diffraction studies revealed that the deposited films are found to possesses orthorhombic structure with a preferential orientation along (111) plane. The microstructural parameters such as crystallite size, strain, dislocation density and texture coefficient are calculated from X-ray diffraction studies. Optical absorption measurements are used to estimate the band gap value of tin sulfide thin films deposited at various bath temperatures. Scanning electron microscopy (SEM) is used to study the surface morphology. SEM images reveal agglomeration of small grains into larger with the increase in bath temperature. AFM images show uniformly shaped grains in electrodeposited SnS thin films. The composition of SnS thin film is analyzed using an energy dispersive analysis by X-rays (EDX) and stoichiometric composition is achieved for films deposited at higher bath temperature. The experimental observations are discussed in detail.