Minority carrier blockade in MIND model solar cells

Abstract

A continuous amorphized a-Si nanostructure with sharp a-Si/c-Si heterointerfaces is inserted in a c-Si wafer by medium-energy P ion implantation followed by a thermal treatment at 500 °C. New photovoltaic phenomena in the mesoscopically transformed material are expected and were presented recently. The simulation of the band structure taking into account the differences between the two Si phases of the MIND (multi-interface novel device) model solar cell indicates the presence of a high barrier blocking the minority carriers, which are photogenerated in the bulk superficial region of the wafer. Consequently, the collection efficiency (i.e. collected carriers versus penetrating photons) is deteriorated in UV. Collection efficiency and EBIC measurements were used to give a theoretical and experimental analysis of the causes and the consequences of such a deterioration on the photocurrent.