CdTe/CdS核壳结构量子点超快载流子动力学

李霞; 冯东海; 何红燕; 贾天卿; 单璐繁; 孙真荣; 徐至展

doi:10.7498/aps.61.197801

摘要

在水相合成CdTe以及CdTe/CdS核壳结构量子点基础上, 利用基于抽运-探测技术的瞬态差分透射技术研究了CdTe量子点以及不同CdS壳层厚度的CdTe/CdS量子点的最低激子能态的超快激发与弛豫动力学. 研究表明:相比于CdTe,CdTe/CdS量子点的电子空穴由于空间分离,其所需的激发时间要长于电子空穴空间重叠态所需要的激发时间.随着壳层厚度的增加, 量子点表面的钝化有效地减少了表面态相关弛豫机理,并延长相对应的弛豫时间.

关键词:

Abstract

On the basic of the synthesis of CdTe/CdS core/shell quantum dots (QDs) in aqueous phase, we study ultrafast carrier dynamic behaviors of CdTe/CdS QDs with different shell thicknesses, by using femtosecond time-resolved transmission spectroscopy. The results show that both the buildup time of the lowest exciton state and its following relaxation time become longer as CdS shell thickness increases. The results also indicate that the buildup rate of a space-separate exciton is slower than that of a space-overlapped exciton, and that carrier relaxation changes from surface-defect related mechanism into surface-passivated charge separation regime, which is consistent with steady-state absorption and photoluminescence experiments.

Keywords:

作者及机构信息

1.
中科院上海光学精密机械研究所,强场激光物理国家重点实验室, 上海 201800;

2.
华东师范大学精密光谱科学与技术国家重点实验室,上海 200062

基金项目: 国家重点基础研究发展计划(批准号:2010CB923203)、国家自然科学基金(批准号: 10904038)和上海科委(批准号: 09JC1404700, 10PJ1403400,11JC1403500)资助的课题.

Authors and contacts

1.
State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China;

2.
State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China

Funds: Project supported by the State Key Development Program for Basic Research of China (Grant No. 2010CB923203), the National Natural Science Foundation of China (Grant No. 10904038), and the Shanghai Municipal Science and Technology Commission (Grant Nos. 09JC1404700, 10PJ1403400, 11JC1403500).

参考文献

[1]	Peng X G, Schlamp M C, Kadavanich A V, Alivisatos A P 1997 J. Am. Chem. Soc. 119 7019
[2]	Barnham K, Marques J L, Hassard J, O'Brien P 2000 Appl. Phys. Lett. 76 1197
[3]	Gao M Y, Lesser C, Kirstein S, Mohwald H, Rogach A L, Weller H 2000 J. Appl. Phys. 87 2297
[4]	Mattoussi H, Mauro J M, Goldman E R, Anderson G P, Sundar V C, Mikulec F V, Bawendi M G 2000 J. Am. Chem. Soc. 122 12142
[5]	Jaiswal J K, Mattoussi H, Mauro J M, Simon S M 2003 Nat. Biotechnol. 21 47
[6]	An L M, Yang Y Q, Song W S, Su W H, Zeng Q H, Chao K F, Kong X G 2009 Acta Phys. Sin. 58 7914 (in Chinese) [安利民,杨延强,宋维斯,苏文辉,曾庆辉,朝克夫,孔祥贵 2009 物理学报 58 7914]
[7]	Chuang C H, Lo S S, Scholes G D, Burda C 2010 J. Phy. Chem. Lett. 1 2530
[8]	Chuang C H,Doane T L,Lo S S,Scholes G D,Burda C 2011 ACS Nano. 5 6016
[9]	Gu Z Y, Zou L, Fang Z, Zhu W H, Zhong X H 2008 Nanotechnology 19 135604
[10]	Zeng Q H, Kong X G, Sun Y J, Zhang Y L, Tu L P, Zhao J L, Zhang H 2008 J. Phys. Chem. C 112 8587
[11]	Zeng R S, Zhang T T, Liu J C, Hu S, Wan Q, Liu X M, Peng Z W, Zou B S 2009 Nanotechnology 20 095102
[12]	Padilha L A, Neves A A R, Cesar C L, Barbosa L C, Brito Cruz C H 2004 Appl. Phys. Lett. 85 3256

施引文献

[1]	Peng X G, Schlamp M C, Kadavanich A V, Alivisatos A P 1997 J. Am. Chem. Soc. 119 7019
[2]	Barnham K, Marques J L, Hassard J, O'Brien P 2000 Appl. Phys. Lett. 76 1197
[3]	Gao M Y, Lesser C, Kirstein S, Mohwald H, Rogach A L, Weller H 2000 J. Appl. Phys. 87 2297
[4]	Mattoussi H, Mauro J M, Goldman E R, Anderson G P, Sundar V C, Mikulec F V, Bawendi M G 2000 J. Am. Chem. Soc. 122 12142
[5]	Jaiswal J K, Mattoussi H, Mauro J M, Simon S M 2003 Nat. Biotechnol. 21 47
[6]	An L M, Yang Y Q, Song W S, Su W H, Zeng Q H, Chao K F, Kong X G 2009 Acta Phys. Sin. 58 7914 (in Chinese) [安利民,杨延强,宋维斯,苏文辉,曾庆辉,朝克夫,孔祥贵 2009 物理学报 58 7914]
[7]	Chuang C H, Lo S S, Scholes G D, Burda C 2010 J. Phy. Chem. Lett. 1 2530
[8]	Chuang C H,Doane T L,Lo S S,Scholes G D,Burda C 2011 ACS Nano. 5 6016
[9]	Gu Z Y, Zou L, Fang Z, Zhu W H, Zhong X H 2008 Nanotechnology 19 135604
[10]	Zeng Q H, Kong X G, Sun Y J, Zhang Y L, Tu L P, Zhao J L, Zhang H 2008 J. Phys. Chem. C 112 8587
[11]	Zeng R S, Zhang T T, Liu J C, Hu S, Wan Q, Liu X M, Peng Z W, Zou B S 2009 Nanotechnology 20 095102
[12]	Padilha L A, Neves A A R, Cesar C L, Barbosa L C, Brito Cruz C H 2004 Appl. Phys. Lett. 85 3256

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