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首页> 外文期刊>Journal of Applied Physics >Photoluminescence dynamics of ensemble and individual CdSe/ZnS quantum dots with an alloyed core/shell interface
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Photoluminescence dynamics of ensemble and individual CdSe/ZnS quantum dots with an alloyed core/shell interface

机译：具有合金核/壳界面的整体和单个CdSe / ZnS量子点的光致发光动力学

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摘要

A comprehensive study of the photoluminescence dynamics in newly developed CdSe/ZnS quantum dots with alloyed core/shell interfaces is presented. Time-correlated single photon counting is used to measure the decay of exciton luminescence from both the ensemble and individual quantum dots. For decreasing emission wavelength (i.e., for smaller dots), the ensemble data reveal increasing total decay rates with greater variation. This systematic change is expected for emitters with stronger quantum confinement and more influenced by the surface/interface trap states. In experiments performed on single quantum dots, the photoluminescence trajectories exhibit two-state blinking behavior. The distributions of the "off-state probability density are described by an average power-law exponent of 1.5 ± 0.2, while the average decay rate of emission from the threshold-discriminated "on"-states is estimated to be 0.035 ±0.004 ns!~(-1). We suggest that in core/shell quantum dots with a large bandgap offset, the compositionally graded energy profile at the interface may not be smooth enough to suppress nonradiative Auger recombination and prevent blinking.
机译：提出了对新开发的具有合金化的核/壳界面的CdSe / ZnS量子点中的光致发光动力学的综合研究。时间相关的单光子计数用于测量来自集合体和单个量子点的激子发光的衰减。对于减小的发射波长（即，对于较小的点），集合数据揭示出总的衰减率增加且变化更大。对于具有更强的量子约束并且受表面/界面陷阱态的影响更大的发射器，可以预期这种系统的变化。在对单个量子点进行的实验中，光致发光轨迹表现出两种状态的闪烁行为。 “断态概率密度”的分布由1.5±0.2的平均幂律指数来描述，而从阈值区分的“导通”状态的平均发射衰减率估计为0.035±0.004 ns！ 〜（-1）。我们建议在带隙偏移较大的核/壳量子点中，界面处的成分渐变能量分布可能不够平滑，无法抑制非辐射俄歇复合并防止闪烁。

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  • 来源
    《Journal of Applied Physics》 |2011年第10期|p.336-341|共6页
  • 作者

    Daniel Ratchford; Konrad Dziatkowski; Thomas Hartsfield; Xiaoqin Li; Yan Gao; Zhiyong Tang;

  • 作者单位

    Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA;

    Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA;

    Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA;

    Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA;

    National Center for Nanoscience and Technology, Beijing, People's Republic of China;

    National Center for Nanoscience and Technology, Beijing, People's Republic of China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);
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  • 正文语种 eng
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