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^\∘ C, has been studied. Elemental analysis of the films shows sulfur deficiency, which increases at higher annealing temperatures (Tₐ). The SnS structure in the as-deposited and annealed films remains orthorhombic. With an increase in Ta_, the grain size and the surface roughness are reduced. The electrical resistivity also decreases with increasing Tₐ. The variation of activation energy and optical parameters with Ta_ has been explained by taking into account the degree of preferred orientation of the grains. The films annealed at 100^\∘ C show some unusual features compared to those annealed at other temperatures.