Optical characteristics of NiO thin film on glass formed by Chemical spray pyrolysis

Abstract

Electochromic material came to public attention around 30 years ago, nickel oxide(NiO) thin film(which is one of the inorganic electrochromic material) has grown on cleaned glass substrate at 498 oK temperature using spray pyrolysis deposition technique of thickness(1451.8A0).UV.-VIS. spectra of the film was studied by using the optical absorbance measurements which were taken in the spectral region from 300nm to 1100nm. The transmittance and reflectance spectra of the film in the UV.-VIS. region were also studied. Optical Constants such as optical allowed and forbidden energy band gap of direct transition, absorption coefficient, extinction coefficient, refractive index and optical conductivity, were evaluated from these spectra. The film was found to exhibit high transmittance(~55-87%) and high absorbance values at ultraviolet region which they decrease rapidly in the visible / near infrared region. Optical allowed band energy for direct transition was (3.694eV) and the forbidden one was(3.653eV).