Space-charge region recombination in monocrystalline silicon-based barrier structures with long lifetimes and its impact on key characteristics of high-efficiency solar cells

The recombination rate in the space charge region (SCR) of a silicon-based barrier structure with long Shockley-Reed-Hall lifetime is calculated theoretically taking into account the concentration gradient of excess electron-hole pairs in the base region. The effects of the SCR lifetime and the applied voltage on the structure’s ideality factor are analyzed. The ideality factor is significantly reduced by the concentration gradient of electron-hole pairs. This mechanism provides an increase of the effective lifetime compared to the case when it is insignificant, which is realized at sufficiently low pair concentrations. The theoretical results are shown to be in agreement with experimental data.