Recombination properties of grain boundaries inpolycrystalline silicon under illumination

Abstract

This paper provides a theoretical study ofrecombination at the grain boundary (GB) in polysilicon underoptical illumination. The model is based on the assumptions ofa Gaussian energy distribution of the GB interfacestates and the acceptor- and donor-like interface states,and unequal capture cross sections of these GBstates for electrons and holes in polycrystalline materials. Withthe condition that we consider the GB material asamorphous silicon, which means that the bandwidth is about1.5 eV, the dependence of the GB potential barrierheight ({V}g), interface and effective recombinationvelocities of minority carriers at the edge of space-chargeregions ({S}(0), {S}({w})) and interfacerecombination current density ({J}R(0)) on theillumination level is investigated. Furthermore, the influenceof different dopant concentration in the grain({N}d) on the parameters ({S}(0),{S}({w}), {J}R(0)) is alsoinvestigated. The results indicate that {S}(0),{S}({w}) and {J}R(0) increase withincreasing {N}d under identicalillumination levels (Δ{E}f).