Optical Characterization of rf-Magnetron Sputtered Nanostructured SnO2 Thin Films

Tin oxide (SnO2) thin films are deposited by rf-magnetron sputtering and annealed at various temperatures in the range of 100-500°C for 15min. Raman spectra of the annealed films depict the formation of a small amount of SnO phase in the tetragonal SnO2 matrix, which is verified by x-ray diffraction. The average particle size is found to be about 20-30nm, as calculated from x-ray peak broadening and SEM images. Various optical parameters such as optical band gap energy, refractive index, optical conductivity, carrier mobility, carrier concentration etc. are determined from the optical transmittance and reflectance data recorded in the wavelength range 250-2500nm. The results are analyzed and compared with the data in the literature.