Analysis of the generation mechanism of the S-shaped J–V curves of MoS2/Si-based solar cells

Amorphous–microcrystalline MoS 2 thin films are fabricated using the sol-gel method to produce MoS 2 /Si-based solar cells. The generation mechanisms of the S-shaped current density–voltage ( J – V ) curves of the solar cells are analyzed. To improve the performance of the solar cells and address the problem of the S-shaped J – V curve, a MoS 2 film and a p + layer are introduced into the front and back interfaces of the solar cell, respectively, which leads to the formation of a p–n junction between the p-Si and the MoS 2 film as well as ohmic contacts between the MoS 2 film and the ITO, improving the S-shaped J – V curve. As a result of the high doping characteristics and the high work function of the p + layer, a high–low junction is formed between the p + and p layers along with ohmic contacts between the p + layer and the Ag electrode. Consequently, the S-shaped J – V curve is eliminated, and a significantly higher current density is achieved at a high voltage. The device exhibits ideal p–n junction rectification characteristics and achieves a high power-conversion efficiency (CE) of 7.55%. The findings of this study may improve the application of MoS 2 thin films in silicon-based solar cells, which are expected to be widely used in various silicon-based electronic and optical devices.