Collection efficiency of heterojunction solar cells

Abstract
The dependence of the generation efficiencyk, the collection efficiencyQ, and the current efficiency\sigma = kQof a heterojunction solar cell on the two semiconductor bandgapsE_{g1}andE_{g2}is investigated. It is assumed that the two semiconductors have ideal absorption characteristics. It is shown that a heterojunction solar cell can exhibit a better current efficiency σ than a homojunction solar cell, if the semiconductor with the larger bandgap is situated at the illuminated side of the junction.