On the optical properties of SnO2 thin films prepared by sol-gel method

Tin oxide (SnO₂) thin films are prepared by spin coating onto well-cleaned glass substrates using stannous chloride and methanol solution as complexing agent. Films of different thicknesses are annealed at 400° C. Optical properties are studied using UV-Visible spectrophotometer. The films are highly transparent in the visible region. It is found that transmission increases in coated glass (∼92%) than uncoated glass. This may find applications in antireflection coating. Energy band gaps obtained are in the range of 4.10–4.12 eV. Refractive index variation with thickness is also studied and is between 1.77–1.91. The thicknesses of the film are of the order 2300, 3500 and 4800 ?. These results have been discussed in the light of literature.