Interdigitated back-contact double-heterojunction GaInP/GaAs solar cells

Abstract

Interdigitated back-contact (IBC) silicon solar cells are coming of age, but the potential of IBC configurations for compound semiconductor solar cells is yet to be explored. We outline an approach to generalize the diffusion-driven charge transport (DDCT) method, previously studied for IBC light-emitting diodes, to develop DDCT solar cells, enabling an IBC double-heterojunction structure. In particular, we simulate and compare the electrical performance of a GaInP/GaAs DDCT solar cell with an ideal one-dimensional reference cell to establish how the lateral dimensions of the DDCT structures affect their operation. Also, the suitability of the DDCT solar cells for concentration photovoltaics is explored. The results show that the DDCT solar cells with a finger pitch of approximately 10μm can match and even outperform the ideal reference structure under the AM1.5G solar spectrum, due to reduced Shockley-Read-Hall recombination. At high solar concentrations, the performance of the smallest pitch DDCT structure is essentially identical with the reference structure up to 100 suns. This suggests that combining the benefits offered by the IBC design with compound semiconductors could allow the development of an entire family of more efficient solar cells.