Electronic Bandgap and Edge Reconstruction in Phosphorene Materials
† Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
‡Center for Nanophase Materials Sciences and §Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
∥ School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
Nano Lett., 2014, 14 (11), pp 6400–6406
DOI: 10.1021/nl502892t
Publication Date (Web): October 24, 2014
Copyright © 2014 American Chemical Society
*E-mail: mhupan@gmail.com (M.P.)., *E-mail: meuniv@rpi.edu (V.M.).
Single-layer black phosphorus (BP), or phosphorene, is a highly anisotropic two-dimensional elemental material possessing promising semiconductor properties for flexible electronics. However, the direct bandgap of single-layer black phosphorus predicted theoretically has not been directly measured, and the properties of its edges have not been considered in detail. Here we report atomic scale electronic variation related to strain-induced anisotropic deformation of the puckered honeycomb structure of freshly cleaved black phosphorus using a high-resolution scanning tunneling spectroscopy (STS) survey along the light (x) and heavy (y) effective mass directions. Through a combination of STS measurements and first-principles calculations, a model for edge reconstruction is also determined. The reconstruction is shown to self-passivate most dangling bonds by switching the coordination number of phosphorus from 3 to 5 or 3 to 4.
Keywords:
Phosphorene;
scanning tunneling microscopy/spectroscopy;
direct bandgap;
monatomic step edges;
density functional theory;
self-passivation
Nano Lett., 2014, 14 (11), pp 6400–6406
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