Effect of growth temperatures on the surface morphology, optical analysis, dielectric constants, electric susceptibility, Urbach and bandgap energy of sprayed NiO thin films

Abstract

Thin films of nickel oxide (NiO) were deposited on glass substrates at a different temperature of growth using spray pyrolysis. Optical properties were examined using spectral measurement at a wavelength range of 300–2500 nm. Optical constants (n and k) were calculated from corrected transmittance and correct reflection. The data obtained show that the direct transition (Eg) decreased from 3.738 to 3.146 eV and the change in indirect transmission from 2.790 to 2.049 eV with increasing temperature. On the contrary, it was found that the Urbach energy (band tail width), the EU has decreased from 0.184 to 0.104 eV. This behavior is believed to be associated with increased growth temperature. Optical conductivity, reflectivity, dielectric constants, volume and surface energy loss functions, electrical susceptibility and relaxation time were discussed as functions for growth temperatures. Of these results, NiO films were rated as an excellent material for optoelectronic applications and a potential candidate for solar cell applications due to their ability to improve.