Excitonic nonlinear absorption in CdS nanocrystals studied using Z-scan technique

被引:73
作者
He, J
Ji, W
Ma, GH
Tang, SH
Elim, HI
Sun, WX
Zhang, ZH
Chin, WS
机构
[1] Natl Univ Singapore, Dept Phys, Singapore 117542, Singapore
[2] Natl Univ Singapore, Dept Chem, Singapore 117542, Singapore
关键词
D O I
10.1063/1.1711183
中图分类号
O59 [应用物理学];
学科分类号
摘要
Irradiance dependence of excitonic nonlinear absorption in cadmium sulfide (CdS) nanocrystals has been studied by using Z-scan method with nanosecond laser pulses. The wavelength dependence of nonlinear absorption has also been measured near the excitonic transition of 1S(e)-1S(3/2)(h). We observe the saturable absorption, which can be described by a third-order and a fifth-order nonlinear process for both 3.0-nm-sized and 2.3-nm-sized CdS nanocrystals. The experimental results show that the excitonic nonlinear absorption of CdS nanocrystals is greatly enhanced with decreasing particle size. A two-level model is utilized to explain both irradiance and wavelength dependence of the excitonic nonlinearity. (C) 2004 American Institute of Physics.
引用
收藏
页码:6381 / 6386
页数:6
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