Stable low-recombination n-Si/TiO2 hole-blocking interface and its effect on silicon heterojunction photovoltaics

TiO₂ deposited on (100) crystalline silicon at near room temperature results in a hole-blocking, electron-transparent heterojunction. In this paper, we show that this interface can have a minority carrier recombination velocity on the order of 100 cm/s, which is stable for over 5 months in air. Second, we model the effect of such interfaces to replace the diffused n⁺/n (back surface field) layer at the cathode of p⁺/n and double heterojunction crystalline silicon solar cells. Simulations show that using TiO₂/n-Si with the measured values of interface recombination velocity as a replacement for the n⁺/n diffusion at the cathode contact would yield power conversion efficiencies greater than 23%.