Preparation And Study Of CIGS Thin Film Solar Cell Window Layer And Transparent Conductive Layer

Owing to the outstanding electro-optical properties, CIGS thin-film solar cells have proven to be the most promising photovoltaic devices. Recently, its transparent conductive layer and window layer are studied intensively because of their impact on the performance of solar cells.ZnO window layer, Al doped ZnO (AZO) transparent conductive layer, and ZnO/AZO bilayer was prepared by magnetron sputtering. To meet the requirement of CIGS thin-film solar cells, the influences of sputtering power, working pressure and other process parameters on electro-optical properties were discussed. The phase structure and surface morphology of the as-prepared films were measured by XRD and SEM. The composition of each chemical element was analysized ED AX. And the optical transmittance and resistivity were observed by UV-visible-near-infrared spectrophotometer and four-probe tester, respectively.The results indicate that ZnO and AZO thin films were along the (002) plane preferential growth, the transmittance between 400 nm to 1400 nm has reached more than 85%. Their resistivity decreased significantly to 10-1 magnitude. The surface and cross-sectional morphology shows that ZnO and AZO grow well. The thickness of the ZnO and AZO are respectively 200nm and 600 nm. It is found that the optical, electrical properties and thickness of bilayer film are close to the requirement of CIGS cells. The corresponding process pamameters are listed as follows. The working pressure is 1.6 Pa, sputtering power is 80 W, sputtering time is 5 minutes for ZnO film, and 1.8 Pa,105 W,20 minutes for AZO film.