Bandgap narrowing in silicon solar cells considering the p-type doping material

Bandgap narrowing (BGN) in p-type silicon is a sensitive parameter for determining the performance of pn junction devices, like solar cells. Previous work in the existing literature does not take into account the dopant used as acceptor. Considering that the impurity energy level can vary from 46 meV above the valence band for Si:B, to 156 meV for Si:In, we studied how this variation affects the BGN. A general equation for BGN is derived as a function of the doping concentration and the impurity energy level. We calculate the BGN and critical concentrations for the metal-nonmetal transition for Si:B, Si:Ga, Si:AI and Si:In. The critical concentration varies from 5 x 10(18) cm(-3) for Si:B to 1.84 x 10(30) cm(-3) for Si:In. The impact of BGN on the open circuit voltage of monocrystalline silicon Solar cells is calculated as a function of the doping concentration. Copyright (C) 1996 Elsevier Science Ltd