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

TL;DR

This paper theoretically analyzes how space-charge region recombination affects the key characteristics of high-efficiency silicon solar cells, highlighting the role of concentration gradients and their impact on device lifetime and ideality factor.

Contribution

It introduces a theoretical model accounting for excess carrier concentration gradients in SCR recombination, aligning with experimental data for silicon-based barrier structures.

Findings

Concentration gradients significantly reduce the ideality factor.

SCR lifetime and applied voltage influence recombination rates.

Theoretical results agree with experimental observations.

Abstract

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.