Excitonic Effects in Tungsten Disulfide Monolayers on Two-Layer Graphene

详细信息    查看全文

• 作者：Cristina E. Giusca ; Ivan Rungger ; Vishal Panchal ; Christos Melios ; Zhong Lin ; Yu-Chuan Lin ; Ethan Kahn ; Ana Laura Elías ; Joshua A. Robinson ; Mauricio Terrones ; Olga Kazakova
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：August 23, 2016
• 年：2016
• 卷：10
• 期：8
• 页码：7840-7846
• 全文大小：416K
• 年卷期：0
• ISSN：1936-086X

文摘

Light emission in atomically thin heterostructures is known to depend on the type of materials and the number and stacking sequence of the constituent layers. Here we show that the thickness of a two-dimensional substrate can be crucial in modulating the light emission. We study the layer-dependent charge transfer in vertical heterostructures built from monolayer tungsten disulfide (WS₂) on one- and two-layer epitaxial graphene, unravelling the effect that the interlayer electronic coupling has on the excitonic properties of such heterostructures. We bring evidence that the excitonic properties of WS₂ can be effectively tuned by the number of supporting graphene layers. Integrating WS₂ monolayers with two-layer graphene leads to a significant enhancement of the photoluminescence response, up to 1 order of magnitude higher compared to WS₂ supported on one-layer graphene. Our findings highlight the importance of substrate engineering when constructing atomically thin-layered heterostructures.