Properties of Amorphous SnO₂ Thin Films, Prepared by Thermal Evaporation

摘要

Tin oxide (SnO₂) thin films of thickness in the range 100-600 nm are prepared on glass substrates by thermal evaporation at ambient temperatures. The films are characterized by recording their transmittance measurements, X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) images and energy dispersion X-ray analysis (EDAX). It is found that the films have high transmittance and non-sharp absorption edge. XRD diffractograms showed that the films are amorphous and the SEM micrographs depicted that the surfaces are smooth, uniform and well covered with the material. The EDAX analysis showed that the films are deficient in oxygen. Indirect optical bandgap energy is determined and Urbach tailing in the bandgap is observed and the width of the tail which is related with disorder and localized states is estimated.