Relation between Non-Radiative Recombination in the Depletion Region and the Carrier Concentration in the Wide-Gap Emitter of a Heterojunction Solar Cell

The reduction of the non-radiative recombination rate by modifying the solar cell structure without improving the material quality is discussed. Our calculations show that adopting a heterojunction design instead of a homojunction design can lead to a reduction of the non-radiative recombination rate in the depletion region due to formation of a depletion region in the wide–gap emitter material, which has a lower intrinsic carrier density. We experimentally confirm the relation between the non-radiative recombination rate in the depletion region and the carrier concentration in the wide-gap emitter layer.