Preparation And Property Research Of ZnO Films Deposited By Electrochemical Deposition Method

Copper indium gallium selenium thin film solar cell(CuIn1-xGaxSe2 solar cells,referred to CIGS)is a new kind thin film solar cell developed in the last century.The first CIGS solar cell was produced by pulling method in Bell Labs(CIGS is based on the CIS evolved).From then on CIGS solar cells became the research focus in all over the world and developed quickly.Recently,there has been growing interests in CIGS solar cells from both fundamental and applied viewpoints.In 2010,ZSW reported that CIGS solar cells with a record efficiency of 20.3%had been prepared.ZnO thin film as n-type window layer is composed of low resistance ZAO and high-resistivity i-ZnO,which is core part of built-electric field of PN junction in CIGS solar cells.So recently,the research for ZnO thin films is widely noted.Zinc oxide(ZnO)thin films were deposited on ITO,low-resistance ZAO thin films and high-resistance ZAO thin films substrate by electrochemical deposition method.We analysis the properties of ZnO thin films prepared at different time,ZnO thin films were characterized by X-ray diffraction(XRD)and scanning electron microscope(SEM).A four-point probe was used to determine the resistivity of the films.The optical transmittance of ZnO thin films was measured by UV-visible spectrum,and we compare the properties of ZnO thin films prepared at different substrates,finally obtain best deposition time and substrate,which can be good for CIGS solar cell.The experimental results show when deposition time is five mintues,we can obtian better ZnO films prepared on ITO,low-resistance ZAO and high-resistance ZAO substrate.ZnO films were prepared on ITO substrate,the maximum transmittance of ZnO films reaches to 73%,and the resistance of ZnO thin film is 10?,ZnO 'films were prepared on low-resistance ZAO substrate,the maximum transmittance of ZnO films reaches to 87%,and the resistivity of ZnO thin film is 2.0x 10-3?·cm,ZnO films were prepared on high-resistance ZAO substrate,the maximum transmittance of ZnO films reaches to 82%,and the resistance of ZnO thin film is 14O?.We compare the properties of ZnO thin films prepared at different substrates,we can find that ZAO/ZnO thin films prepared low-resistance ZAO substrate,whose resistivity can reaches to 6.0×10-4Q.cm,and the maximum transmittance of ZAO/ZnO films reaches to 90%at wave length from 600nm to 800nm,In essence,good-quality double-layers thin films of ZnO/ZAO play an important role in CIGS solar cells.