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The PV cells currently deployed are made using crystalline or multicrystalline silicon. Although the systems work extremely well the technology is not yet cost competitive with other forms of power
generation. To reduce production costs thin film solar cells are being developed. These minimise costs because thinner layers can be used to absorb the incident light, (as the materials used are better absorbers of light than silicon), minimising material costs and because low cost production methods can be used. The thin film materials investigated are amorphous Si (a-Si:H), cadmium telluride (CdTe) and the chalcopyrite based semiconductor materials such as copper indium galliumdi selenide (CIGS). Of these materials the chalcopyrite materials are the most promising because cells can be produced with stable efficiencies greater than those achieved with a-Si:H solar cells and they do not have the environmental problem associated with Cd as occurs with CdTe-based technology. Although the highest efficiencies (20.0 % on lab scale) in thin film solar cells have been achieved using copper indium gallium diselenide (CIGS), there is some concern with the lack of abundance of the gallium (Ga) used in those devices. In this work, this problem has been dealt by replacing Ga with Al to develop novel CuInAlSe2 (CIAS) based solar cell devices. The CIAS based devices which were developed have the structure: soda lime glass, molybdenum back contact, chalcopyrite absorber layer, CdS buffer layer, ZnO:Al transparent conducting oxide layer (TCO), top contact grid. The seminar will mainly discuss several issues related to deposition of CIAS thin films by two stage method (sputtering + selenisation). It also contain some results obtained during research work carried out on CIAS absorber thin films at Northumbria Photovoltaic Applications Centre, UK.
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