Structural and Optical characterization of Nanocrystalline SnO2 thin film prepared by spray pyrolysis technique

Abstract

Nanocrystalline Tin Oxide SnO2 thin films have been grown on cleaned glass substrates at 450 C○ using spray pyrolysis deposition technique, prepared from two precursor solutions SnCl2.2H2O and SnCl4.5H2O.The XRD analyses showed that these films have polycrystalline in nature with tetragonal rutile structure with preferred orientation of (110),(200),(211) and the crystalline size (grain size) of thin films are found to vary from 32.6 to 56.98 nm .
UV -VIS spectra of the films were studied using the optical absorbance measurements which were taken in the spectral region from 190 nm to 1100 nm. The transmittance and ref1ectance spectra of the films in the UV -VIS region were also studied. Optical Constants such as optical band gap, absorption coefficient and extinction coefficient, were evaluated from these spectra. All the films were found to exhibit high transmittance greater than (~ 85 %), and high absorbance values at ultraviolet region which they decrease rapidly in the visible / near infrared region. The optical band gap energy was found 3.98 eV for sample A and 3.97 eV for sample B.