Solar Cell Efficiency Increase at High Solar Concentration, by Thermionic Escape via Tuned Lattice- Matched Superlattices

General p-i-n solar cell structures are suitable hosts for regions where quantum effects might occur; excess photo-carriers can be developed in quantum traps (quantum wells) grown along the direction of the cell (from p to n region). The cell absorbs at two different wavelengths (a) the host (Ehost=hc/λhost band-gap) and (b) the optical gap wavelength (Esolar-photon=hc/λoptical gap). The optical gap of the superlattice can be tuned to desired solar photon energy values (e.g. 1eV photons, Figure-1), with optical gap matching the desired solar photon flux (Figure 1) [1]. 2. Introduction and background