Al and Ga doped ZnO films prepared by a sol–gel spin coating technique

Abstract

ZnO is a promising material suitable for variety of novel electronic applications including sensors, transistors, and solar cells. Intrinsic ZnO film has inferiority in terms of electronic properties, which has prompted researches and investigations on doped ZnO films in order to improve its electronic properties. In this work, aluminium (Al) doped ZnO (AZO) and gallium (Ga) doped ZnO (GZO) films were coated on glass substrates by a sol–gel spin coating technique. AZO and GZO films were examined using XRD, AFM, FESEM, UV–vis spectroscopy, and Hall Effect measurement system to investigate the structural, morphology, optical transmittance, and electronic properties of the films. Highly c-axis oriented and transparent AZO and GZO films with distinct peak at 34.5° corresponding to (002) orientation were obtained. The decrease of (002) peak was observed with higher doping level. The optical transmittances in the visible region are in the range of 80–95%. Samples with 1at% Al and 2at% Ga showed the lowest electrical resistivity. The correlation of the doping level of Al and Ga on doped ZnO films will be revealed in this work.