Abstract
The relaxation of the to electronic states of CdSe semiconductor nanocrystals is followed by infrared pump-probe spectroscopy. Fast (1 ps) and slow (>200 ps) components are observed. Using different capping molecules to control the hole states, we show how the intraband relaxation slows down as the hole is in a shallow trap, a deep trap, or a charge-separated complex, providing strong support for an electron-hole Auger coupling. The slow component corresponds to an energy relaxation rate orders of magnitude slower than in bulk systems. It may be the first indication of the phonon bottleneck effect long expected in strongly confined quantum dots.
- Received 1 December 1998
DOI:https://doi.org/10.1103/PhysRevB.60.R2181
©1999 American Physical Society