Analysis of short circuit current loss in rear emitter crystalline Si solar cell

摘要

Short circuit current (J_(sc)) loss in rear emitter crystalline Si solar cell is analyzed in detail by a 2D device simulation and compared with the experimental results. There is a significant loss in J_(sc) for the rear emitter n-Si solar cell with an n-type doped front surface field (FSF) when the base substrate resistivity is low. It is due to an increase in recombination in the FSF region led by a less barrier height for minority carriers with a lower substrate resistivity. The barrier height less than 0.1 eV causes large loss in J_(sc). To achieve higher J_(sc) for the cells with FSF, the control of the doping concentration in FSF, the substrate thickness, and the barrier height for the minority carriers are important. A rear emitter heterojunction Si solar cell with an amorphous Si passivation layer shows no substrate resistivity dependence on J_(sc) since an amorphous Si possess a higher barrier height and a long bulk lifetime of more than a few milliseconds.