中国物理B ›› 2012, Vol. 21 ›› Issue (10): 107801-107801.doi: 10.1088/1674-1056/21/10/107801

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Investigation of ultrafast dynamics of CdTe quantum dots by femtosecond fluorescence up-conversion spectroscopy

姚关心a b, 吕良宏b, 桂美芳c, 张先燚b, 郑贤锋b, 季学韩b, 张宏d, 崔执凤a b   

  1. a Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China;
    b Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu 241000, China;
    c College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, China;
    d Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1090 GD Amsterdam, The Netherlands
  • 收稿日期:2012-02-11 修回日期:2012-04-07 出版日期:2012-09-01 发布日期:2012-09-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11074003 and 20973001) and the Key Program of Educational Commission of Anhui Province of China (Grant No. KJ2010A132).

Investigation of ultrafast dynamics of CdTe quantum dots by femtosecond fluorescence up-conversion spectroscopy

Yao Guan-Xin (姚关心)a b, L¨u Liang-Hong (吕良宏)b, Gui Mei-Fang (桂美芳)c, Zhang Xian-Yi (张先燚)b, Zheng Xian-Feng (郑贤锋)b, Ji Xue-Han (季学韩)b, Zhang Hong (张宏)d, Cui Zhi-Feng (崔执凤)a b   

  1. a Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China;
    b Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu 241000, China;
    c College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, China;
    d Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1090 GD Amsterdam, The Netherlands
  • Received:2012-02-11 Revised:2012-04-07 Online:2012-09-01 Published:2012-09-01
  • Contact: Zhang Hong, Cui Zhi-Feng E-mail:h.zhang@uva.nl; zfcui@mail.ahnu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11074003 and 20973001) and the Key Program of Educational Commission of Anhui Province of China (Grant No. KJ2010A132).

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摘要： The ultrafast carrier relaxation processes in CdTe quantum dots are investigated by femtosecond fluorescence up-conversion spectroscopy. Photo-excited hole relaxing to the edge of the forbidden gap takes a maximal time of ～ 1.6 ps with exciting at 400 nm, depending on the state of the photo-excited hole. The shallow trapped states and deep trap states in the forbidden gap are confirmed for CdTe quantum dots. In addition, Auger relaxation of trapped carriers is observed to occur with a time constant of ～ 5 ps. A schematic model of photodynamics is established based on the results of the spectroscopy studies. Our work demonstrates that femtosecond fluorescence up-conversion spectroscopy is a suitable and effective tool in studying the transportation and conversion dynamics of photon energy in a nanosystem.

关键词: CdTe quantum dots, femtosecond fluorescence up-conversion spectroscopy, ultrafast dynamics, nanomaterial

Abstract: The ultrafast carrier relaxation processes in CdTe quantum dots are investigated by femtosecond fluorescence up-conversion spectroscopy. Photo-excited hole relaxing to the edge of the forbidden gap takes a maximal time of ～ 1.6 ps with exciting at 400 nm, depending on the state of the photo-excited hole. The shallow trapped states and deep trap states in the forbidden gap are confirmed for CdTe quantum dots. In addition, Auger relaxation of trapped carriers is observed to occur with a time constant of ～ 5 ps. A schematic model of photodynamics is established based on the results of the spectroscopy studies. Our work demonstrates that femtosecond fluorescence up-conversion spectroscopy is a suitable and effective tool in studying the transportation and conversion dynamics of photon energy in a nanosystem.

Key words: CdTe quantum dots, femtosecond fluorescence up-conversion spectroscopy, ultrafast dynamics, nanomaterial

中图分类号:  (High resolution nonlinear optical spectroscopy)

  • 78.47.N-
78.67.Hc (Quantum dots)