On the impact of the metal work function on the recombination in passivating contacts using quasi-steady-state photoluminescence​
Anh Huy Tuan Le1, Johannes P. Seif1, Thomas G. Allen2, Robert Dumbrell1, Christian Samundsett3, Ziv Hameiri1
1University of New South Wales, Sydney, Australia
/2King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
/3The Australian National University, Canberra, Australia

Understanding the impact of metal contacts on the recombination within a passivated silicon wafer is crucial for the optimization of photovoltaic devices. To investigate the effect of their work function, a selection of metals was applied to aluminum-oxide-passivated n-type crystalline silicon wafers. The saturation current density of the metalized contact (J0,metal) was determined using the quasi-steady-state photoluminescence method and used as a figure of merit to quantify the effect. We found that J0,metal increases with the work function and that this effect is modulated with the passivation layer thickness. It is more pronounced for thinner passivation layers, which can be attributed to a stronger metal-induced band bending, while thicker ones shield the interface more efficiently leading to insignificant changes in J0,metal. Based on these findings, we suggest a suitable work function range to optimize contact recombination in silicon-based solar cells.

Area: Sub-Area 4.4: Passivated Contacts, Carrier Selective Contacts and Hetero-Junction Structures