Passivation effect of SiOx interfacial layer in MoOx hole selective contact

摘要

Transient metal oxides (TMO) have recently attracted large attention because of their potential as carrier selective contacts for silicon heterojunction (SHJ) solar cells. The large work function of TMO such as MoO_3, WO_3, and V_2O_5 induces a band bending on the c-Si surface, creating a band energy gradient that repels the electrons and allow the formation of an inversion layer at the interface. As a result, rectifying properties similar to those obtained with pn-junctions can be achieved. Through this approach, an impressive efficiency of 22.5% has been achieved using a MoO_3/a-Si:H stack as the hole selective contact in SHJ solar cells.In contrast, the passivation effect achieved in MoO_x-c-Si/MoO_x structures without passivation layers has been attributed to both band bending and unintentional silicon oxide formation at the MoO_x/c-Si interface.