Effective Photon Recycling and Super Long Lived Minority Carriers in GaInP/GaAs Heterostructure Solar Cell: A Time-Resolved Optical Study

We present a study of recombination dynamics and lifetimes of minority carriers in a GaInP/GaAs heterostructure single-junction solar cell by using a variable-temperature time-resolved photoluminescence (TRPL) technique. It was found that the minority carriers, i.e., electrons, in the p-type GaInP base layer have super long lifetimes of ~220 μs under the excitation of nanosecond laser pulses. On the basis of a newly developed model for time-resolved luminescence of a localized-state ensemble [e.g., Z. C. Su and S. J. Xu, Sci. Rep. 7, 13 (2017)], it is revealed that as much as 38% of photons emitted by localized carriers may be involved in the photon recycling in the GaInP base layer. The effective photon recycling is believed to be an important factor that causes the super long lifetime of the minority carriers, and can help reduce the radiative recombination loss of photogenerated carriers in heterostructure based solar cells.