Influence of annealing on physical properties of evaporated SnS films

The effect of annealing on the composition, crystal structure, surface features and electro-optical properties of tin mono-sulfide ( SnS) films, deposited by thermal evaporation at 300 degrees C, has been studied. Elemental analysis of the films shows sulfur deficiency, which increases at higher annealing temperatures ( T-a). The SnS structure in the as-deposited and annealed films remains orthorhombic. With an increase in T-a, the grain size and the surface roughness are reduced. The electrical resistivity also decreases with increasing T-a. The variation of activation energy and optical parameters with T-a has been explained by taking into account the degree of preferred orientation of the grains. The films annealed at 100 degrees C show some unusual features compared to those annealed at other temperatures.