CdTe vs. GaAs solar cells — A modeling case study with preliminary experimental results

A modeling study has been undertaken to compare CdTe versus GaAs solar cells in order to explore and forecast the possible evolution of CdTe solar cell performance while using GaAs solar cells as a benchmark. A complementary experimental comparison study of two almost identical MgCdTe/CdTe/MgCdTe and AlGaAs/GaAs/AlGaAs double-heterostructure (DH) samples grown by MBE guided the solar cell modeling. Both DH samples give strong photoluminescence at room temperature (RT) while time-resolved photoluminescence measurements reveal a 50 ns carrier lifetime at RT for the MgCdTe/CdTe/MgCdTe DH sample. The modeling results based on these experimental data indicate that CdTe solar cells can achieve efficiency in the range of 24-27%, depending on the carrier lifetime, under the AM1.5G spectrum.