Control of excitonic absorption by thickness variation in few-layer GaSe
Control of excitonic absorption by thickness variation in few-layer GaSe
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DOI：
10.1103/physrevb.100.045404
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发表时间：
2019-07-08
影响因子：
3.7
通讯作者：
Brida, Daniele
中科院分区：
文献类型：
--
作者：
Budweg, Arne;Yadav, Dinesh;Brida, Daniele
我们在单个层的水平上控制GaSe的厚度，并通过高灵敏度的差分透射测量研究相应的光吸收。当层数小于临界值8时，可以观察到激子跃迁的抑制。通过从头算模型，我们能够将这种行为与能带结构的基本变化联系起来，这种变化导致在薄GaSe中形成一个形状为倒置墨西哥帽的价带。光学性质的厚度控制调制为基于单一材料的功能光电器件的开发提供了有吸引力的资源。
We control the thickness of GaSe on the level of individual layers and study the corresponding optical absorption via highly sensitive differential transmission measurements. Suppression of excitonic transitions is observed when the number of layers is smaller than a critical value of 8. Through ab initio modelling we are able to link this behavior to a fundamental change in the band structure that leads to the formation of a valence band shaped as an inverted Mexican hat in thin GaSe. The thickness-controlled modulation of the optical properties provides attractive resources for the development of functional optoelectronic devices based on a single material.