Indium phosphide solar cells: P+-N or N+-P?

A modeling study has been carried out to determine whether p⁺ -n or n⁺-p InP solar cells give better performance. The physical model used was standard except that radiative recombination was modified to allow for photon recycling. The numerical model combined one-dimensional solutions of the transport equations with the Handy model for series resistance. The parameters optimized were: front SRV, emitter doping, emitter thickness, number, and width of grid fingers. Calculations were done with only radiative recombination in the bulk and with a state-of-art level of SRH (Schottky-Read-Hall) recombination. The results suggest that in the absence of SRH recombination p⁺-n with η=23.4% are better than n⁺-p with η=23.1%