Improvement in passivation quality and open-circuit voltage in silicon heterojunction solar cells by the catalytic doping of phosphorus atoms

Abstract

We apply phosphorus (P) doping to amorphous silicon (a-Si)/crystalline silicon (c-Si) heterojunction solar cells realized by exposing c-Si to P-related radicals generated by the catalytic cracking of PH3 molecules (Cat-doping). An ultrathin n+-layer formed by P Cat-doping acts to improve the effective minority carrier lifetime (τeff) and implied open-circuit voltage (implied Voc) owing to its field effect by which minority holes are sent back from an a-Si/c-Si interface. An a-Si/c-Si heterojunction solar cell with a P Cat-doped layer shows better solar cell performance, particularly in Voc, than the cell without P Cat-doping. This result demonstrates the feasibility of applying Cat-doping to a-Si/c-Si heterojunction solar cells, owing to the advantage of the low-temperature (<200 °C) process of Cat-doping.