Analysis of solar cells using the IBIC technique

Abstract

The ion beam induced charge (IBIC) technique has been applied to investigate the relative efficiency in polycrystalline silicon solar cells. Relative efficiency is defined as the charge pulse height normalised with respect to the maximum charge collected. Using IBIC, solar cells have been imaged with microbeam both normal and transverse to the collection junction to obtain the charge collection. The measured charge collection at the grain boundary (GB) of the crystals is then compared to computer simulation to obtain the diffusion length of the bulk and the effective recombination velocity (SGBeff) at the GB. The dependence of the relative efficiency on the carrier injection level is then investigated using both MeV alphas and molecular hydrogen. We also show that SGBeff depends on the excess carrier injection level.