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Surface Analysis of WSe2 Crystals: Spatial and Electronic Variability.
Rafik Addou1, Robert M Wallace1
1Department of Materials Science, Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States.
ACS Applied Materials & Interfaces
|September 8, 2016
Summary
Defects and impurities significantly impact the electronic properties of tungsten diselenide (WSe2), a promising 2D material. Controlling material quality at the nanoscale is crucial for advancing optoelectronics and nanoelectronics.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Layered semiconductor compounds offer alternatives to graphene for electronic applications.
- Tungsten diselenide (WSe2) is a two-dimensional material with significant potential in optoelectronics and nanoelectronics.
- WSe2 is utilized in constructing novel 3D architectures with enhanced functionalities.
Purpose of the Study:
- To investigate the topography and electronic properties of WSe2.
- To understand the impact of defects and impurities on WSe2 electronic behavior.
- To explore the spatial variation in electronic structure and Fermi level position.
Main Methods:
- Scanning Tunneling Microscopy and Spectroscopy (STM/STS) for surface topography and electronic properties.
- X-ray Photoelectron Spectroscopy (XPS) for elemental and chemical state analysis.
- Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for elemental composition.
Main Results:
- STM revealed atomic-scale imperfections and electronic structure variations due to defects/impurities.
- STS and photoemission demonstrated spatial variations in the Fermi level position.
- Core-level analysis indicated the presence of diverse doping levels within the WSe2.
Conclusions:
- A high concentration of defects and impurities strongly influences the electronic properties of the WSe2 surface.
- Achieving controllable, high-quality 2D materials at the nanoscale remains a significant challenge.
- Further research attention is required for advancing the synthesis of high-quality 2D materials.
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