Ultra-thin silicon oxide tunnel layer passivated contacts for screen-printed n-type industry solar cells

Abstract

Effects of the ultra-thin silicon oxide (SiOx) on tunnel oxide passivated contact solar cells (TOPCon) are investigated in this paper. The experiment is fabricated to study the TOPCon electrical performance with different SiOx thickness and the champion efficiency is achieved by the TOPCon with a 1.5 nm SiOx layer, with Voc 698.93 mV, Jsc 40.14 mA/cm2, FF 81.03 and efficiency 22.73 %. For futher understanding, EDNA2 and AFORS-HET are used to simulate the relationship between the SiOx thickness, rear SRV and the doping concentration in n+ layer. It indicates that the total J0 at the SiOx-(c-Si) interface (J0, interface) can be affected by the phosphorus concentration at the SiOx-(c-Si) interface. Besides, due to the variation of SRV or P-doped concentration, different recombination mechanisms, including auger recombination and surface recombination, will dominant the total J0, interface. In addition, the sensitivity of TOPCon solar cells electrical performance to SiOx thickness can be affected by rear SRV, and the sensitivity of TOPCon solar cells electrical performance to rear SRV can be affected by SiOx thickness.