在CdSe/CdTe二维体异构结构中,激子-声子相互作用控制电荷转移状态动态
Raj Pandya1, Richard Y S Chen1, Alexandre Cheminal1
1Cavendish Laboratory , University of Cambridge , J.J. Thompson Avenue , CB3 0HE , Cambridge , United Kingdom.
Journal of the American Chemical Society
|October 9, 2018
概括
CdSe/CdTe纳米板中的电荷转移激子受到声子的影响,影响光发射特性. 了解这些激子-声子相互作用是提高二维半导体技术量子产量的关键.
科学领域:
- 材料科学
- 纳米技术
- 量子物理
背景情况:
- CdSe/CdTe芯冠纳米板是具有发光应用潜力的二维半导体.
- 这些异构结构中的兴奋子动力学和声子相互作用尚未完全理解.
研究的目的:
- 在CdSe/CdTe纳米小板中研究激子动态和激子-声子相互作用.
- 了解声子对电荷转移激子形成和光发光的影响.
主要方法:
- 五秒振动光谱学
- 温度分辨率的光发光 (PL)
- 温度依赖的结构测量
主要成果:
- 电荷转移 (CT) 激子通过超快的电子转移 (~70 fs) 和域激子扩散 (~5 ps) 形成.
- 接口声模式 (~120 cm-1) 定位CT激子并扩大CT PL频谱.
- 由于激子扩散不完整和激子-声子散射,PL量子产量高 (在4K时约为单位),但在室温下降 (约为50%).
结论:
- 激子-声子相互作用显著影响二维CdSe/CdTe异构的光学特性.
- 优化界面结构和激子扩散对于最大化这些材料中的PL量子产量至关重要.
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