发布时间：2018-03-12

文章标题：2D Materials: One dimensional metallic edges in atomically thin WSe2 induced by air exposure

内容：

Our  paper:

One dimensional metallic edges in atomically thin WSe₂ induced by air exposure

has been published on 2D Materials.

http://iopscience.iop.org/article/10.1088/2053-1583/aab0cd/meta 

 

Transition metal dichalcogenides are a unique class of layered two-dimensional (2D) crystals with extensive promising applications. Tuning the electronic properties of low-dimensional materials is vital for engineering new functionalities. Surface oxidation is of particular interest because it is a relatively simple method of functionalization. By means of scanning probe microscopy and x-ray photoelectron spectroscopy, we report the observation of metallic edges in atomically thin WSe₂ monolayers grown by chemical vapor deposition on epitaxial graphene. Scanning tunneling microscopy shows structural details of WSe₂ edges and scanning tunneling spectroscopy reveals the metallic nature of the oxidized edges. Photoemission demonstrates that the formation of metallic sub-stoichiometric tungsten oxide (WO_2.7) is responsible for the high conductivity measured along the edges. Ab initio calculations validate the susceptibility of WSe₂ nanoribbon edges to oxidation. The zigzag terminated edge exhibits metallic behavior prior the air-exposure and remains metallic after oxidation. Comprehending and exploiting this property opens a new opportunity for application in advanced electronic devices.

 

This work was led by Dr. Rafik Addou and Prof. Robert M Wallace in The University of Texas at Dallas. Yi Pan contributed to this project by performing LT STM/STS measurement at 5K, together with Dr. Stefan Fölsch and Prof. Randall Feenstra, in Paul Drude Institute.