Spectral response and dark I-V characterization of polycrystalline Si solar cells with conventional and selective emitters

High efficiency (up to 16.4%) 4cm² polycrystalline silicon solar cells have been analyzed, using a simple analytical model to account for both spectral response and dark IV characteristics. The model allows the deduction, from measured data, of important cell parameters such as surface and bulk recombination velocities, emitter and base saturation currents. These parameters are discussed in terms of solar cell structure, wafer properties and process conditions. Increased base doping is shown to lead to a transition from base-dominated to emitter-dominated saturation current. The measured open circuit voltages can be accounted for, including the record values (636 mV) found for the highest base doping