Surface photovoltage spectroscopy for texture and passivation processes monitoring in black silicon solar cells

Abstract

This paper deals with the use of Surface Photovoltage Spectroscopy (SPS) as a monitoring technique to optimize the manufacturing process of black silicon (B-Si) based solar cells. The results of the application of the SPV to study different texturization (surface micro/nano texturing) and passivation schemes in black silicon-based solar cells are presented. It is shown how the SPV signal is sensitive to different procedures such as conventional alkaline chemical etching and a subsequent treatment to obtain B-Si. So, the effect on the SPV signal of the use of different metals (Ag and Cu) as catalyst in the nanotexturing processing (by Metal-Assisted Chemical Etching), as well as different plasma pressures during the passivating annealing in ammonia atmosphere were explored. The magnitude of the SPV signal after passivation was found to be indicative of the final performance of the solar cell without the need of metal contacts deposition. Result obtained by SPV measurements were correlated with the lifetimes of minority carrier measured using a commercial lifetime tester and with those obtained by Kelvin Probe Force Microscopy (KPFM). The presented results indicate how SPV can be used for quality control purposes at any stage of solar cell fabrication.