Physical Properties of ZnO:Al Films Prepared at Low Temperature in High Power on Flexible Substrate Using for Solar Cell
Abstract
Transparent and conductive aluminium-doped zinc oxide (AZO) thin films were deposited on a polyethylene terephthalate (PET) substrate at a low temperature by radio-frequency sputtering using an AZO target composed of ZnO:Al2O3 (2 wt.%). We report a method to deposit in high power radio frequency of ZnO:Al (AZO) films on PET substrate without any crack and low resistivity. The sputtering was carried out in an Ar gas (99.99%) atmosphere with varying RF power ranging from 100 to 300 W. The effects of RF power on morphology, structural, resistivity and optical properties in low and high RF power were investigated. The structural properties of as-deposited films were analysed by X-ray diffraction managements (XRD) confirmed that films have hexagonal wurtzits structure and a strong preferred c-axis orientation (002). Resistivity as low as 1.1*10-3 ȍcm was achieved for the film deposited at 250 W and 0.2 Pa. High optical transmittance (95%) was exhibited when films were deposited at RF powers below 150W. Band gap energies ranged from 3.36 to 3.39 eV.