Charge-Induced Second-Harmonic Generation in Bilayer WSe2
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- 作者：Huakang Yu ; Deep Talukdar ; Weigao Xu ; Jacob B. Khurgin ; Qihua Xiong
- 刊名：Nano Letters
- 出版年：2015
- 出版时间：August 12, 2015
- 年：2015
- 卷：15
- 期：8
- 页码：5653-5657
- 全文大小：339K
- ISSN：1530-6992
文摘
Controlling nonlinear light鈥搈atter interaction is important from a fundamental science point of view as well as a basis for future optoelectronic devices. Recent advances in two-dimensional crystals have created opportunities to manipulate nonlinear processes electrically. Here we report a strong second-harmonic generation (SHG) in a 2D WSe2 bilayer crystal caused by a back gate field. This unusual process takes place only when the gate polarity causes charge accumulation rather than depletion. Analysis based on a bond鈥揷harge model traces the origin of SHG to the nonuniform field distribution within a single monolayer, caused by the accumulated submonolayer screening charge in the tungsten plane. We name this phenomenon charge-induced SHG (CHISHG), which is fundamentally different from the field- or current-induced SHG. Our findings provide a potentially valuable technique for understanding and noninvasive probing of charge and current distributions in future low dimensional electronic devices.