The effects of dopant concentration and deposition temperature on the structural, optical and electrical properties of Ga-doped ZnO thin films

Abstract

In the present work, we have deposited Ga-doped ZnO (GZO) thin films by magnetron sputtering technique using nanocrystalline particles elaborated by sol–gel method as a target material. The gallium doping concentration was varied from 1.0 to 5.0at.%. The effect of the deposition temperature and the dopant concentration, on the physical properties of the GZO thin films was analyzed. The as-deposited films with a thickness of about 300nm were polycrystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The crystallite size ranged from 25 to 32nm, depending on the deposition temperature and Ga at.%. A minimum electrical resistivity value of 2.2×10−3Ωcm and a maximum mobility of 16.42cm2/Vs were obtained under the optimal deposition conditions. The optical transmittance measurements show that all films are highly transparent in the visible wavelength region with an average transmittance of about 90%.