Electron and hole relaxation pathways in II-VI semiconductor nanocrystals

Victor I Klimov, Ch Schwarz, X. Yang, D. W. McBranch

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Femtosecond (fs) broad-band transient absorption (TA) is used to study the intra-band relaxation and depopulation dynamics of electron and hole quantized states in CdSe nanocrystals (NC's) with a range of surface properties. Instead of the drastic reduction in the energy relaxation rate expected due to a 'phonon bottleneck', we observe a fast sub-picosecond 1P-to-1S relaxation, with the rate enhanced in NC's of smaller radius. We use fs IR TA to probe electron and hole intraband transitions, which allows us to distinguish between electron and hole pathways leading to the depopulation of NC quantized states. In contrast to electron relaxation, which is controlled by NC surface passivation, depopulation of hole quantized states is extremely fast (sub-ps-to-ps time scales) in all types samples, independent of NC surface treatment (including NC's overcoated with a ZnS layer). Our results indicate that ultrafast hole dynamics are not due to trapping at surface defects, but rather arise from relaxation into intrinsic NC states.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium - Proceedings
PublisherMaterials Research Society
Pages211-216
Number of pages6
Volume536
Publication statusPublished - 1999
EventProceedings of the 1998 MRS Fall Meeting - The Symposium 'Advanced Catalytic Materials-1998' - Boston, MA, USA
Duration: Nov 30 1998Dec 3 1998

Other

OtherProceedings of the 1998 MRS Fall Meeting - The Symposium 'Advanced Catalytic Materials-1998'
CityBoston, MA, USA
Period11/30/9812/3/98

Fingerprint

Nanocrystals
Electrons
Surface defects
Electron transitions
II-VI semiconductors
Passivation
Surface properties
Surface treatment

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this

Klimov, V. I., Schwarz, C., Yang, X., & McBranch, D. W. (1999). Electron and hole relaxation pathways in II-VI semiconductor nanocrystals. In Materials Research Society Symposium - Proceedings (Vol. 536, pp. 211-216). Materials Research Society.

Electron and hole relaxation pathways in II-VI semiconductor nanocrystals. / Klimov, Victor I; Schwarz, Ch; Yang, X.; McBranch, D. W.

Materials Research Society Symposium - Proceedings. Vol. 536 Materials Research Society, 1999. p. 211-216.

Research output: Chapter in Book/Report/Conference proceedingChapter

Klimov, VI, Schwarz, C, Yang, X & McBranch, DW 1999, Electron and hole relaxation pathways in II-VI semiconductor nanocrystals. in Materials Research Society Symposium - Proceedings. vol. 536, Materials Research Society, pp. 211-216, Proceedings of the 1998 MRS Fall Meeting - The Symposium 'Advanced Catalytic Materials-1998', Boston, MA, USA, 11/30/98.
Klimov VI, Schwarz C, Yang X, McBranch DW. Electron and hole relaxation pathways in II-VI semiconductor nanocrystals. In Materials Research Society Symposium - Proceedings. Vol. 536. Materials Research Society. 1999. p. 211-216
Klimov, Victor I ; Schwarz, Ch ; Yang, X. ; McBranch, D. W. / Electron and hole relaxation pathways in II-VI semiconductor nanocrystals. Materials Research Society Symposium - Proceedings. Vol. 536 Materials Research Society, 1999. pp. 211-216
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