Enhanced Structural, Optical and Electrochemical Properties of Pulsed Laser Deposited Binary Zinc and Molybdenum Oxide Nanostructured Thin Films

Abstract

The binary metal oxides of ZnO and MoO3 (ZMO) nanostructured thin films were prepared by pulsed laser deposition at different temperatures such as 298(as deposited), 623, 773 and 923K at 10Hz laser repetition rates for 30 min. The films were characterized by XRD, UV-Visible spectroscopy and IV measurements. The XRD discloses the amorphous nature of the film deposited below 773K. Few peaks which were seen in 923K sample revealed the formation of ZnMoO4 and Zn3Mo2O9 for the binary ZMO thin films. The optical energy band-gap was measured using Tauc plot and was found to be 2.4 to 2.7eV. These films were investigated by electrochemical impedance spectroscopy over a frequency range of 1Hz–1MHz, for measuring temperatures lying in 298K-473K domain. The frequency response of the imaginary impedance (Z′′) shows relaxation behavior along every measuring temperature. The binary ZMO pulsed laser deposited at high temperatures demonstrates better semiconducting behavior. The activation energy (Ea) which is minimum for high temperature PLD thin films was determined from the Arrhenius plot based on impedance.