Wide-band-gap InAlAs solar cell for an alternative multijunction approach

Abstract

We have fabricated an In0.52Al0.48As solar cell lattice-matched to InP with efficiency higher than 14% and maximum external quantum efficiency equal to 81%. High quality, dislocation-free InxAl1−xAs alloyed layers were used to fabricate the single junction solar cell. Photoluminescence of InxAl1−xAs showed good material quality and lifetime of over 200 ps. A high band gap In0.35Al0.65As window was used to increase light absorption within the p-n absorber layer and improve cell efficiency, despite strain. The InAlAs top cell reported here is a key building block for an InP-based three junction high efficiency solar cell consisting of InAlAs/InGaAsP/InGaAs lattice-matched to the substrate.