Effect of oxygen annealing treatment on structural, optical and electrical properties of In doped ZnO thin films prepared by PLD technique

Abstract

ZnO/Si heterojunctions have potential applications in optoelectronic devices. The study of their characteristics is quite important to optimize their properties. We report here the effect of annealing on different proprieties of In doped ZnO thin films deposited on glass substrate and p-type silicon (100) wafers using pulsed laser ablation. The structural, optical and electrical properties were studied with various techniques. After heat treatment, the transmittance increases which confirms the reduction of roughness and band gap energy from 3.44 eV to 3.39 eV. Further, the electrical measurements show an increase in conductivity and evidences the presence of a small polaron jump and a variable range jump during the conduction process at high and low temperatures, respectively. Current-voltage confirms the presence of space charge zone. Finally, capacitance-voltage measurements at different frequencies were performed to estimate the acceptor concentrations and the built-in potential. Such transparent and smooth layer is interesting to concept optoelectronic devices bases on ZnO/Si heterojunction.