Optical characterization of tin oxide thin films synthesized by DC sputtering

Tin Oxide thin films have a large transmittance in the visible region of the electromagnetic spectrum, owing to the large bandgap, which varies from 3.6 eV to about 4.2 eV. In general, the films are transparent from a wavelength of 400nm to about 2000nm. The transparency decreases with increasing carrier concentration due to the larger absorbance by the electrons. The Tin Oxide films were deposited under a vacuum of 0.1 mbar on glass substrate by DC sputtering. The structural characterization was done using XRD spectral analysis which was followed by UV-VIS-NIR Spectroscopy. Optical properties of these films are investigated in the entire UV-Visible-IR region. The observed absorption edge lies at 3.8 eV for undoped tin oxide.