- Bullock, James;
- Wan, Yimao;
- Hettick, Mark;
- Zhaoran, Xu;
- Phang, Sieu Pheng;
- Yan, Di;
- Wang, Hanchen;
- Ji, Wenbo;
- Samundsett, Chris;
- Hameiri, Ziv;
- Macdonald, Daniel;
- Cuevas, Andres;
- Javey, Ali
Over the past five years, there has been a significant increase in both the intensity of research and the performance of crystalline silicon devices which utilize metal compounds to form carrier-selective heterocontacts. Such heterocontacts are less fundamentally limited and have the potential for lower costs compared to the current industry dominating heavily doped, directly metalized contacts. A low temperature (≤230 °C), TiO x /LiF x /Al electron heterocontact is presented here, which achieves mΩcm 2 scale contact resistivities ρ c on lowly doped n-type substrates. As an extreme demonstration of the potential of this heterocontact, it is trialed in a newly developed, high efficiency n-type solar cell architecture as a partial rear contact (PRC). Despite only contacting ≈1% of the rear surface area, an efficiency of greater than 23% is achieved, setting a new benchmark for n-type solar cells featuring undoped PRCs and confirming the unusually low ρ c of the TiO x /LiF x /Al contact. Finally, in contrast to previous versions of the n-type undoped PRC cell, the performance of this cell is maintained after annealing at 350–400 °C, suggesting its compatibility with conventional surface passivation activation and sintering steps.