Solution growth of polycrystalline silicon on glass at low temperatures

Large area (15 cm²) polycrystalline silicon thin films, with an average thickness of about 20 μm and large grain size up to 5 mm², have been grown on glass from various molten metal and metal alloy solutions at temperatures as low as 400°C. Good wetting of the substrate by the solution and supersaturation were found crucial for obtaining successful crystal growth. Silicon crystals with (111) preferred orientation were obtained using slow cooling rates and for thinner film thicknesses, while (110) oriented films were obtained using higher cooling rates and greater film thicknesses. These materials exhibited few crystal defects apart from twinned crystals which are not generally harmful to solar cell performance, and thus have enormous potential for thin film silicon solar cell applications, especially for the multi-junction thin film silicon solar cell structure developed at the Centre for Photovoltaic Devices and Systems, University of New South Wales, Australia