Enhanced Hot-Carrier Effects in InAlAs/InGaAs Quantum Wells

• Published in: IEEE journal of photovoltaics Vol. 4; no. 6; pp. 1526 - 1531
• Main Authors: Hirst, Louise C., Yakes, Michael K., Bailey, Christopher G., Tischler, Joseph G., Lumb, Matthew P., Gonzalez, Maria, Fuhrer, Markus F., Ekins-Daukes, N. J., Walters, Robert J.
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01-11-2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Hot carriers; Hot-carrier solar cell (HCSC); Indium gallium arsenide; Indium phosphide; InGaAs; InP; Photovoltaic cells; Photovoltaic systems; quantum well (QW); Quantum wells; Solar energy; thermalization coefficient; InGaAs; InP; quantum well (QW); Hot-carrier solar cell (HCSC); thermalization coefficient
• ISSN: 2156-3381; 2156-3403
• DOI: 10.1109/JPHOTOV.2014.2355412

Hot-carrier solar cells require absorber materials with restricted carrier thermalization pathways, in order to slow the rate of heat energy dissipation from the carrier population to the lattice, relative to the rate of carrier extraction. Absorber suitability can be characterized in terms of carrier thermalization coefficient (Q). Materials with lower Q generate steady-state hot-carrier populations at lower levels of incident solar power and, therefore, are better able to perform as hot-carrier absorbers. In this study, we evaluate Q = 2.5±0.2 W·K -1 · cm -2 for a In 0.52 AlAs/In 0.53 GaAs single-quantum-well(QW) heterostructure using photoluminescence spectroscopy. This is the lowest experimentally determined Q value for any material system studied to date. Hot-carrier solar cell simulations, using this material as an absorber yield efficiency ~39% at 2000X, which corresponds to a >5% enhancement over an equivalent single-junction thermal equilibrium device.