Effect of Al and Mg Doping on Optical Properties of ZnO Thin Films Prepared by Spin Coating

This paper investigated the influence of aluminum and magnesium doping on the optical and electrical properties of zinc oxide (ZnO) thin films for solar cell application. Zinc acetate dehydrates was used as starting material. Aluminum chloride and tin chloride were added to each solution to serve as dopants. X-ray diffractions were analyzed by X-ray diffraction (XRD) which revealed crystalline and hexagonal wurtzite structure. All the films showed more than 80% transparency in the visible region. The optical band gap of undoped ZnO thin film was found to be 3.12ev while that of Al-doped and Mg-doped ZnO film was estimated to be 3.16eV and 3.26eV respectively. The resistivity of the films measured were 2.51×10-4 Ω cm for Al-doped, 2.53×10-4 Ω cm for mg-doped and 2.61×10-4 Ω cm for undoped ZnO respectively. The quality of the films deposited in this work is a promising window layer component of a solar cell. The variation in the band gap observed in this work could be explained by Burstein?Moss effect which was fully explained in the discussion section of this work.