XRD and electrical studies on AZO thin films deposited via sol-gel technique

This paper reports the structural and electrical characterization of ZnO and ZnO:Al hereafter abbreviated as AZO) transparent conducting thin films. These films were synthesized from non-alkoxide inorganic zinc source (Zn(NO3)2.6H2O with acetate acid, triethanolamine, 2-methoxyethanol, and glycerol, through alcoholic route via sol-gel dip coating method. X-ray diffraction technique (XRD) was employed to investigate sample structure, phase and crystallite size. Sample doped with 2.0% at A1 and post heat treated at 550 degree C shows the lowest sheet resistance (270.9 kΩ/□) with polycrystalline structure. At lower post heat treatment temperature (450 degree C) structure changes from polycrystalline to amorphous with an increase of dopant level that causes higher sheet resistance. In contrast, at higher post heat treatment temperature, amorphous structure becomes polycrystalline and larger crystallite size is observed. The increase in crystallite size is attributed to grain growth phenomena. (Author)