Design and simulations of 24.7% efficient silicide on oxide-based electrostatically doped (SILO-ED) carrier selective contact PERC solar cell

Abstract

Silicon-based passivated emitter and rear cell (PERC) has emerged as a mainstream high-efficiency cell technology in recent years. However, inherent contact recombination loss becomes the main limiting factor in PERC solar cells, limiting the performance of the PERC device toward higher efficiencies close to the Auger limit of 29.4%. Therefore, carrier selective contacts such as polysilicon on oxide (POLO) have been researched and investigated in the past to mitigate contact-related losses. POLO contacts require a heavily doped polysilicon layer on a thin tunnel oxide layer to facilitate the tunnelling of desired charge carrier electron or hole and simultaneously push the other carrier hole or electron back into the substrate. In this work, single-sided POLO contact-based PERC device is investigated, and an alternative approach is projected to avoid the need for a heavily doped polysilicon layer in carrier selective contacts. Silicide on oxide-based electrostatically doped (SILO-ED) carrier selective contact is designed and examined through extensive device simulation using Silvaco based process and device simulations. Four different devices with a planar or textured surface are designed, such as conventional, single POLO, single POLO with ED, and SILO-ED PERCs to have a comparative analysis. Initially, the influence of surface recombination velocity (SRV) (from 102 to 107 cm/s) on the front surface in the case of a non-POLO PERC device has been investigated. Afterwards, the PERC device by employing single-POLO contact on the front surface has been designed and simulated to obtain 23.95% efficiency. Further, the concept ED is introduced, and 24.6% efficient ED-POLO (with 1 nm thick poly-Si) and 24.7% SILO-ED contact-based PERC devices are designed to avoid the need for a heavily doped polysilicon layer. The SILO-ED-based PERC device with 24.7% conversion efficiency is also compared with the Auger limit (29.4%) for the comparative purpose. The work reported in this research article may pave the way for developing highly efficient PERC solar cells.