Effect of Deposition Parameters on Optical and Electrical Properties of SnO2: Al Thin Films Prepared by Spray Pyrolysis Technique for Optoelectronic Devices

Transparent Aluminum doped tin oxide (SnO2:Al) thin films with different Al percentage (1.96%, 3.85%, 5.66%, 7.41% and 9.09%) were fabricated using a low cost spray pyrolysis technique at optimized deposition parameters. Substrate temperature, carrier gas pressure and spray outlet to substrate distance were varied to obtain optimum conditions for deposition. Optical characterization of the deposited films was carried out to the average transmittance, optical constants (refractive index (n) and extinction coefficient (k)) and the band gap. The calculated refractive indexes of the films with various Al concentrations were in the range of 1.469 Al at. % to 1.914 Al at. % w with 5.37% at. % being the optimum, while the average transmittance was between 70% and 80% and band gap of 3.96 eV. The calculated resistivity was in the order of 10-4 Ωcm