Thin-Barrier Strained Quantum Well Superlattice Solar Cells

Quantum wells can improve solar cell conversion efficiency by extending infrared absorption and, in some cases, by suppressing radiative recombination to lower the dark current and increase the operating voltage. In this study, the effect of strained InGaAs/GaAs QWs incorporated in an InGaP-GaAs heterojunction based single junction solar cell has been investigated. The performance of 3-layer In 0.08 Ga 0.92 As/GaAs QWs incorporated in the intrinsic region of the nip deive with varying barrier thicknesses have been compared. The heterojunction design along with a wider bandgap InAlP front window allows superior absorption and low dark current. Despite the incorporation of QWs, minimal to no V oc loss has been observed compared to the baseline design without QWs, which can be attributed to suppressed radiative emission from the devices. All designs exhibit low-dark current characteristics, while the best QW cell conversion efficiency of >26% has been obtained with short circuit current of 30.22 mA/cm2 and open circuit voltage of 1.03V under 1-sun AM1.5G solar spectrum.