Preparation and Characterization of Doped Transparent Zinc Oxide Thin Films for Solar Cell Applications

Abstract

The growing demand for energy has resulted in the research and development of clean and renewable energy technology and related materials. In this work, the effect of acetic acid on the structural, optical and electrical properties of undoped ZnO was studied. Also, the effect of indium and gallium dopants on the structural, optical and electrical properties of ZnO was studied. The ZnO thin films were deposited on glass substrates at 400°C using the spray pyrolysis deposition technique. X-ray diffraction (XRD) results indicated that both undoped and doped ZnO films had (002) preferred orientation. The amount of acetic acid in the precursor solution had an effect on the crystal structure of the undoped ZnO. The undoped ZnO films exhibited high transmittance above 80%. In:ZnO and Ga:ZnO films had transmittance above 60% and 70% respectively. From the Hall Effect measurements, doping improved the conductivity of the ZnO thin films however In:ZnO films showed higher electrical conductivity compared to Ga:ZnO films. Electron probe microanalysis (EPMA) results also confirmed the presence the respective dopants in the thin film samples; indium in In:ZnO and gallium in Ga:ZnO.