Effect of sputtering time on one-step magnetron-sputtered Cu(In,Ga)Se_2 thin films for solar cells

CIGS thin films were produced by one-step magnetron sputtering using a single quaternary-CIGS target in stoichiometric proportion and the influences of sputtering time on the structural,optical,and electrical properties of Cu(In,Ga)Se2(CIGS)thin films were investigated. The phase structure of CIGS thin films were characterized by X ray diffraction(XRD).The morphologies and thicknesses of CIGS thin films were observed by Scanning Electron Microscope(SEM). The absorption coefficient of CIGS thin films were measured by Ultraviolet-visible Spectrophotometer.Four-point probe method was used to test the resistivity of CIGS thin films.The results showed that the thickness of the thin films were thicker,the crystallization of the films were better and the particle size of thin films were bigger with increasing sputtering time,while the resistivity of thin films were lower significantly,and with high absorption coefficient(close to 105 cm-1).CIGS absorber layer performance is very advantageous to improve the light conversion efficiency of the CIGS thin film photovoltaic cell.