Composition and Optical Dispersion Characterization of Nanoparticles ZnO-NiO Thin Films: Effect of Annealing Temperature

Abstract

Thin films of ZnO 0.7 NiO 0.3 have deposited on glass substrates at room temperature by using thermal evaporation technique under vacuum 10 -5 mbar. The optical properties and dispersion parameters of the films have been studied. Changes in direct optical energy band gap of films were confirmed before and after annealing. The optical energy gap E g decreased from 3.11 to 2.86 eV with increasing of annealing temperature to 200 ºC. Some of the optical absorption parameters, such as optical dispersion energies E o and E d , Urbach tails E U , dielectric constant ε, the average values of oscillator strength S o , and wavelength of single oscillator λ o have been reported. An increase in the annealing temperature causes an increase in the average oscillator strength from 62.02 to 87.71 eV.

Microstructure and optical dispersion characterization of nanocomposite sol–gel TiO 2 –SiO 2 thin films with different compositions

“…From this result one could conclude that SiO 2 , a wide energy band oxide, as an additive in TiO 2 , can enlarge the optical band gap of the composite thin films. This increase could be attributed to the crystal growth and reorganization of the films as was previously observed by Raman and SEM analysis [35]. For similar composite sol-gel materials, Vishwas et al observed a slight increase from 3.22 to 3.33 eV for indirect allowed transition when TiO 2 content decreases from 100% to 60% [12].…”

Investigation on the Structural and Optical Properties of NiO Nanoflakes. Chemical Bath Deposition of Ni(OH)2 Thin Films

“…Nowadays, numerous chemical and physical techniques such as the electro-deposition [10], thermal decomposition [11], template synthesis [12], chemical bath deposition (CBD) [13], sol-gel method [14], hydrothermal method [15], spray pyrolysis [16], pulse laser deposition method (PLD) [17], and anodic electrochemical deposition [18] have been employed to enhance the functionality of nanoporous thin films.…”