Nanowire-based solar cells are interesting structures for photovoltaic applications as they enhance properties such as light absorption, trapping efficiency and carrier collection. Consequently, the potential to decrease the cost of photovoltaic energy thanks to these structures is not negligible. However, up to now, their efficiency has been limited mainly because of the recombination at the interfaces and in the volume. The effective minority carrier lifetime is a key parameter which is strongly connected to volume, interface and surface recombination properties. In this work, we have used a purely electrical approach called reverse recovery transient (RRT) to perform measurements of minority carrier lifetime in core-shell nanowire-based solar cells under dark conditions. The structures are based on crystalline silicon nanowires grown on silicon wafers and embedded in a radial amorphous silicon shell. The electrical contacts for this hetero-junction structure are transparent conductive oxide for the front surface and aluminum for the backside. A planar solar cell has also been fabricated to be used as a reference. By comparing RRT measurement on the nanowire-based solar cell and on the planar reference solar cell with simulations, we extract the lifetime of the nanowires.
Daanoune, M., Kohen, D., Kaminski-Cachopo, A., Morin, C., Faucherand, P., Perraud, S., & Blanc-Pélissier, D. (2014). Minority carrier lifetime measurement in nanowire based solar cells by a reverse recovery transient method. In Energy Procedia (Vol. 60, pp. 181–190). Elsevier Ltd. https://doi.org/10.1016/j.egypro.2014.12.333