MULTICRYSTALLINE SILICON SOLAR CELLS ON GLASS BASED ON A LASER CRYSTALLIZATION PROCESS USING A NEW 980 nm DIODE LASER DEVELOPED BY LIMO

摘要

This paper presents the preparation of multicrystalline silicon layers for thin film solar cells on glass by using a line focus diode laser emitting a wavelength of 980 nm. Previously, a diode laser emitting a wavelength of 808 nm was used for this process. For preparation of the solar cells a 5 to 10 μm thick amorphous silicon layer is deposited by high rate electron beam evaporation. The subsequent diode laser process results in a crystalline layer consisting of up to mm sized grains to be used as the absorber layer of the solar cell. The emitter is prepared by epitaxial crystallization of a highly p-doped a-Si thin film by applying an excimer laser. Solar cells based on this laser crystallization process showed efficiencies up to 10%. The new 980 nm diode laser has considerable advantages for up-scaling to an industrial scale, e.g. an up to 50% higher optical power per device than the 808 nm diode laser and more than 100.000 hours life time in a 24/7 production regime. Irradiation of the amorphous silicon layers by 980 nm wavelength laser light yields similar crystal structure as by 808 nm wavelength, however at a similar laser power. The properties of the solar cells prepared by both laser sources are compared.