Title: Gap States at Low-Angle Grain Boundaries in Monolayer Tungsten Diselenide
Authors: Huang, Yu Li
Ding, Zijing
Zhang, Wenjing
Chang, Yung-Huang
Shi, Yumeng
Li, Lain-Jong
Song, Zhibo
Zheng, Yu Jie
Chi, Dongzhi
Quek, Su Ying
Wee, Andrew T. S.
Department of Electrophysics
Keywords: STM/STS;monolayer WSe2;low-angle grain boundaries;dislocation core;gap states;first-principles calculations
Issue Date: Jun-2016
Abstract: Two-dimensional (2D) transition metal dichalcogenides (TMDs) have revealed many novel properties of interest to future device applications. In particular, the presence of grain boundaries (GBs) can significantly influence the material properties of 2D TMDs. However, direct characterization of the electronic properties of the GB defects at the atomic scale remains extremely challenging. In this study, we employ scanning tunneling microscopy and spectroscopy to investigate the atomic and electronic structure of low-angle GBs of monolayer tungsten diselenide (WSe2) with misorientation angles of 3-6 degrees. Butterfly features are observed along the GBs, with the periodicity depending on the misorientation angle. Density functional theory calculations show that these butterfly; features correspond to gap states that arise in tetragonal dislocation cores and extend to distorted six-membered rings around the dislocation core. Understanding the nature of GB defects and their influence on transport and other device properties highlights the importance of defect engineering in future 2D device fabrication.
URI: http://dx.doi.org/10.1021/acs.nanolett.6b00888
ISSN: 1530-6984
DOI: 10.1021/acs.nanolett.6b00888
Volume: 16
Issue: 6
Begin Page: 3682
End Page: 3688
Appears in Collections:Articles