Unified picture of electron and hole relaxation pathways in semiconductor quantum dots
- 7 June 2007
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 75 (24), 245311
- https://doi.org/10.1103/physrevb.75.245311
Abstract
Size dependent electron and hole relaxation dynamics were measured in colloidal CdSe quantum dots with state-to-state specificity. These experiments reveal the electron and hole state-to-state relaxation dynamics with a precision of , allowing quantitative evaluation of the manifold of pathways by which an exciton relaxes in strongly confined quantum dots. These experiments corroborate previously observed confinement induced femtosecond Auger relaxation channels for electrons, but with sufficient precision to quantitatively and unambiguously determine the size dependence of the Auger mechanism. These experiments also show that the hole energy loss rate increases for smaller quantum dots, contradicting known relaxation mechanisms for holes. We propose a confinement enhanced mechanism for hole relaxation in colloidal quantum dots, overcoming the predicted phonon bottleneck for holes. The relative contributions of the relaxation pathways are identified for electrons and for holes. These state selective experiments produce a unified picture of the manifold of relaxation pathways available to both electrons and holes in strongly confined colloidal quantum dots.
Keywords
This publication has 75 references indexed in Scilit:
- Intraband relaxation in CdSe nanocrystals and the strong influence of the surface ligandsThe Journal of Chemical Physics, 2005
- Hole intraband relaxation in strongly confined quantum dots: Revisiting the “phonon bottleneck” problemPhysical Review B, 2002
- SPECTROSCOPY AND HOT ELECTRON RELAXATION DYNAMICS IN SEMICONDUCTOR QUANTUM WELLS AND QUANTUM DOTSAnnual Review of Physical Chemistry, 2001
- Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor NanocrystalsThe Journal of Physical Chemistry B, 2000
- Mechanisms for intraband energy relaxation in semiconductor quantum dots: The role of electron-hole interactionsPhysical Review B, 2000
- Quantization of Multiparticle Auger Rates in Semiconductor Quantum DotsScience, 2000
- Electron and hole relaxation pathways in semiconductor quantum dotsPhysical Review B, 1999
- Intraband relaxation in CdSe quantum dotsPhysical Review B, 1999
- Femtosecond-to-Electron Relaxation in Strongly Confined Semiconductor NanocrystalsPhysical Review Letters, 1998
- Ultrafast energy relaxation in quantum dotsPhysical Review B, 1996