Study On Preparation And Properties Of GIGS Thin Films

Copper indium gallium selenium thin film solar cell(CuIn1-xGxSe2 solar cells,referred to CIGS)as a renewable energy source have been taken as one of the most promising third-generation solar cells due to a lot of advantages,such as high efficiency,stability,low cost,strong radiation resistance,effective use of raw materials and short energy payback time.Therefore many investigators all over the world are attracted to pay more attention to the progress of CIGS thin-film solar cells.CIGS thin films deposited on the substrate in stoichiometric proportions are I-III-VI2 chalcopyrite compound as a p-type semiconductor,which is employed for the absorbing layer in thin-film solar cells.Due to high absorption coefficient(?105cm-1)and adjustable band-gap in the range 1.04-1.67eV,the thin films with the thickness of about 2?m can absorb sufficient amounts of light.Therefore,how to improve the performance of the absorbing layer is the concern of the majority of scholars.CIGS solar cells with the record efficiency of 20.3%on a laboratory scale were reported by ZSW,while the large area of the integrated components highest conversion efficiency is more than 13%.In this paper,CIGS thin films were prepared by bipolar pulse magnetron sputtering using quaternary-CIGS target and one-step vacuum evaporation using a single quaternary-CIGS power on the substrate.In order to determine the optimal process parameter,the influence of the substrate,the target distance,the deposition time,substrate temperature and annealing on composition,crystalline phase,surface morphology,absorption-coefficient,band gap and resistivity of CIGS film were investigated.The experimental results indicated that the CIGS thin films prepared by magnetron sputtering have(112)prepared orientation.The thickness of the film was determined by the sputtering time.The substrate temperature had effect on the crystalline.When the deposition time of 120min,the substrate temperature of 300? and the target distance was set to 65mm,the crystallization of film is the best.The resistivity is smaller.The absorption coefficient of visible light is larger than 0.8x105cm-1,and the band gap is higher than other samples.The change of substrate temperature and evaporation power will affect the crystallization degree,electrical properties and optical properties of the CIGS films by evaporation.When the substrate temperature of 400?and the evaporation power was set to 335W,the crystallization of film is the best.The resistivity is smaller.The absorption coefficient of visible light is more than 0.85 X 105cm-1.The electrical and optical properties of the CIGS films are optimal.The annealing can greatly reduce the film resistivity,also can improve the crystallization of the film and the annealing temperature of 400? is appropriate.