Preparation And Properties Of Absorber Layer Of Cias Thin Film Solar Cell

Energy crisis and environmental pollution problems have become more serious and greatly promoted the development of photovoltaic industry.Solar energy as new, one of the most promising renewable energy sources can effectively solve these two problems.Study on new technology of solar cell development of solar energy resources has become a focus of photovoltaic industry.The absorption layer is a core component of solar cells.The crystal structure of chalcopyrite CuInSe2(CIS) semiconductor thin films for its high conversion efficiency, resistance to radiation and strong, good stability researchers much attention.In this paper, by doping Al element to replace part of In, preparation of CIAS film as the absorption layer of CIAS thin film solar cell, reduce cost. Changing the content of Al element in the film component, adjusting the width of band gap, matched with the solar spectrum better.In this experiment, CIAS thin films have been prepared by vacuum evaporation methodon ordinary glass substrates, combined with vacuum selenium annealing processing.Focusing on the influence of doping elements of Al content, annealing temperature and annealing time on the structure and properties of CIAS thin films.Respectively using X ray diffraction, scanning electron microscope and EDS energy spectrometer, profiler, Holzer effect instrument, ultraviolet visible near infrared spectrophotometer in CIAS thin film structure, morphology, composition, thickness and photoelectric properties were studied.The results show that the crystallization of CIAS thin film prepared by vacuum thermal evaporation are very complete, showing a chalcopyrite crystal structure, and with the(112) crystal face preferred growth. partial substitution of Al for CIS in the lattice of In, reduces the spacing. CIAS thin film conductivity type is P type, the carrier concentration up to 1020 orders of magnitude. With the decrease of Al content, CIAS thin films exhibit structural features of uniform particle size, boundaries clear, dense. CuIn1-xAlxSe2 films deposited by vacuum of selenium annealing, selects the 350~550 ℃ as the annealing temperature,the experiments found that annealing contributes to Cu, In, Al, Se atoms migration, proliferation, reaching well combined with each other,he composition of the film after annealing at 450℃ more close to the ideal ratio, photoelectric properties suitable to be used as the absorber layer of a photovoltaic cell. As the annealing temperature to 450℃, changing the annealing time, the results show that with the increase of annealing time, the resistivity showed first increased and then decreased, carrier concentration and mobility is the opposite, in addition to the annealing time for the 2h film samples outside the band gap of film increases gradually. By contrast, the annealing temperature is 450℃, the annealing time for 1h of CuIn0.7Al0.3Se2 is more suitable for the absorption layer of CIAS thin film solar cell.