Effect of Cu doping on optical and electrical properties of ZnO thin films deposited by spray pyrolysis technique

Abstract

The aim of this work is to study the effect of copper doping and nozzle-substrate distance on the optical and electrical properties of zinc oxide thin films to obtain photoelectric properties which makes it an important candidate in many technological applications. In this work, we have prepared copper-doped zinc oxide thin films (ZnO:Cu) at different atomic percentage (0, 2, 4, 6, 8 at. %) onto glass substrates by ultrasonic spray pyrolysis technique from zinc acetate dehydrate solution and copper chloride dihydrate solution with constant preparation conditions (deposition temperature, deposition time, molar concentration and flow rate of solution). These samples were characterized using the UV-Visible-NIR spectrophotometer and the four-probe technique to study their optical and electrical properties. We notice that these properties are affected by the copper concentration and the nozzle-substrate distance. Where, by increases the Cu concentration or the approach of the substrate to the spray nozzle during preparation, the transmittance, refractive index, band gap, and electrical conductivity of the films are decrease with increasing the both of the thickness and Urbach energy of these films