The road to high efficiency solar cells: selective absorption for full-spectrum operation via GaAs/alloy & GaAs/Ge superlattices

The race for high efficiency solar cells is on. We are exploring in this communication the advantage of quantum size effects in p-i-n solar cell structures, by means of GaAs-Ge successive layers in the intrinsic region. We argue that the advantage of gallium arsenide epitaxial technology and the matching between GaAs and Ge layers may lead to fine tuning of energy values in the intrinsic region. This in turn leads to selective absorption at wavelengths at all ranges desired even to a full spectrum absorption. We conclude with the fact that such designs may push collection efficiency levels to the highly sought threshold of 40%. Our design's advantages include (a) lattice matching (b) selective doping and (c) current generation via thermionic emission and hopping.