Material properties of polysilicon layers deposited by atmospheric pressure iodine vapor transport

Fast (3 μm/min) and direct deposition of large-grain (~20 μm) polycrystalline silicon layers on foreign substrates at intermediate temperatures (~900°C) is achieved by an atmospheric pressure iodine vapor transport technique. A hole Hall mobility of 51 cm ²/V.s at a doping density of 5.5×10¹⁷ cm^-3 was measured in an as-deposited material. After hydrogen passivation, it increased to 76 cm²/V.s. Crystallographic defects mostly consist of less detrimental stacking faults and twins, with a few dislocations. Diagnostic PV devices using an N⁺-a-Si/i-a-Si/APIVT-Si(absorber)/P⁺-CZ-Si structure demonstrated an open-circuit voltage of 0.48 V and 0.58 V at one and 13 suns, respectively. Highly [110]-oriented silicon layers were attained