Detecting electronic structure evolution of semiconductor nanocrystals by magnetic circular dichroism spectroscopy
Detecting electronic structure evolution of semiconductor nanocrystals by magnetic circular dichroism spectroscopy
复制标题
利用磁圆二色光谱检测半导体纳米晶的电子结构演化
DOI：
10.1039/c9nr03630j
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发表时间：
2019
期刊：
影响因子：
6.7
通讯作者：
Tang Zhiyong
中科院分区：
文献类型：
--
作者：
Gao Xiaoqing;Zhang Xiuwen;Yang Xuekang;Zhao Luyang;Han Bing;Alanagh Hamideh Rezvani;Tang Zhiyong
由于纳米晶体的电子能级是凝聚态的，传统的光学和电子学仪器很难探测到纳米晶体在形状变化下的电子态演化。在这里，我们证明了磁圆二色性（MCD）光谱是一种高分辨率的方法来监测这一微妙的进展，由于敏感的塞曼响应电子状态。特别地，第一激子跃迁的MCD强度随着量子点到量子棒的形状变化而指数下降，这是由于价态pz态密度随着z方向上的伸长而增加，这与p±相比对MCD强度的贡献要小得多。这项工作为理解各种半导体纳米材料中的电子态演化提供了一种简单而有效的策略。
The evolution of electronic states of nanocrystals under shape variation is hardly detected by conventional optical and electronic instruments due to the condensed electronic levels of nanocrystals. Herein, we demonstrate that magnetic circular dichroism (MCD) spectroscopy is a high-resolution method to monitor this delicate progress on account of the sensitive Zeeman response to electronic states. In particular, the MCD intensity of the first excitonic transition exponentially decreases with the shape changing from quantum dots to quantum rods owing to the increased density of valence pz state with elongation in the z direction, which contributes much less to MCD intensity compared with p±. This work provides a simple but effective strategy for understanding the electronic state evolution in various semiconductor nanomaterials.