Radiative recombination in strain-balanced quantum well solar cells

The radiative behavior of GaAsP/GaAs/InGaAs strain-balanced quantum well solar cells (SB-QWSC) with 1, 5 and 10 wells was studied. Quantum efficiencies were measured and fitted by the model SOL. Electroluminescence (EL) spectra were predicted according to a generalized detailed balance treatment assuming a quasi-Fermi level separation (QFLS) equal to the applied bias. By comparison to experimental EL spectra, a reduced QFLS was found in all three samples confirming results obtained in strained single and double quantum wells. Photoluminescence (PL) measurements conducted on the single well SB-QWSC showed that the QFLS reduction also occurred in the light as for the strained single well sample.