A STUDY OF OPTICAL BAND GAP AND ASSOCIATEDURBACH ENERGY TAIL OF CHEMICALLY DEPOSITEDMETAL OXIDES BINARY THIN FILMS

[摘要] In this paper, we present the influence of post deposition annealing and varying concentration on the optical properties of NiO, ZnO and Co3O4 thin films, with emphasis on the effect of growth parameters on optical band gap and Urbach energy. Increasing the concentration of each of the precursor solutions decreased the band gap from 3.85eV to 3.75eV for NiO film samples, 3.90eV to 3.85eV for Co3O4 film samples and increased from 3.85eV to 3.88eV for ZnO film samples. With respect to annealing temperature, no clear trend was observed. The fundamental absorption edge shifted toward a lower photon energy with respect to concentration for NiO and Co3O4 thin films whereas it shifted to higher photon energy for ZnO thin films. An inverse relation between band gap energy and Urbach energy was found. The range of band gaps are suitable for applications in various solar architecture, optoelectronics and high frequency applications.

[学科分类] 生物技术

[关键词] Band gap;Temperature;Thin film;Photon energy;Concentration