Evidence of two-photon absorption in strain-free quantum dot GaAs/AlGaAs solar cells

We report the fabrication procedure and the characterization of an Al0.3Ga0.7As solar cell containing high-density GaAs strain-free quantum dots grown by droplet epitaxy. The production of photocurrent when two sub-bandgap energy photons are absorbed simultaneously is demonstrated. The high quality of the quantum dot/barrier pair, allowed by the high quality of nanostructured strain-free materials, opens new opportunities for quantum dot based solar cells. Left: Scheme of the fabricated quantum dot solar cell. Right: 1 × 1 μm2 image of the dot layer. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.