Room-temperature exciton absorption engineering in II-VI quantum wells

We observe large room-temperature exciton absorption in the wavelength region around 0.8 μm in CdTe-based quantum wells. This comes as a result of a room-temperature exciton engineering concept particularly suitable for II-VI quantum wells where, by appropriate quantum-well confinement, the exciton binding energy approaches and exceeds the LO phonon energy. This condition results in a drastic reduction of the exciton-LO phonon coupling. As a consequence, the temperature-induced exciton broadening, due to scattering events with LO phonons, is reduced and large excitonic absorption is observed at room temperature.