Photovoltaic properties of polycrystalline silicon films thickenedby laser melting

摘要

During RF CVD of a-Si:H onto glass an Ar⁺ laser beamwas scanned to crystallize a seed layer. Subsequently every 20 nm newdeposited a-Si:H was molten by one light pulse from a KrF laser, so thatthe laser processing did not take any additional time. A highlyconducting p⁺ region close to the glass as transparentelectrode and a p⁺pn junction within the film were depositedwithout a doping gas. REM, TEM images and XRD measurements confirmed anepitaxial growth of large crystallites. The self structuredsilicon/glass interface and film surface show increased scattering whichsupports light absorption. Transients of open circuit voltage after apulsed generation by UV light at the p⁺, as well as at the nside, were contactless sensed to evaluate the PV quality of films asdeposited. A lifetime of more than 5 μs and a diffusion length forholes of more than 25 μm were determined