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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
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Remote epitaxial interaction through graphene
Celesta S Chang1,2, Ki Seok Kim1,2, Bo-In Park1,2
1Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science Advances
|October 20, 2023
Summary
Remote epitaxy uses a 2D van der Waals layer to guide crystal growth, enabling atomic alignment without direct contact. This study visually confirms remote epitaxy at the atomic scale using barium titanate on graphene.
Area of Science:
- Materials Science
- Nanotechnology
- Surface Science
Background:
- Remote epitaxy is a crystal growth technique utilizing a 2D material layer to template growth on a substrate.
- Defects in 2D materials can lead to direct epitaxy or lateral overgrowth, complicating remote epitaxy observation.
- Distinguishing remote epitaxy from other 2D material-based epitaxy mechanisms is crucial for its application.
Purpose of the Study:
- To visually confirm and characterize remote epitaxy at the atomic scale.
- To differentiate unique phenomena specific to remote epitaxy.
- To investigate the influence of substrate properties on remote epitaxy.
Main Methods:
- Growing barium titanate (BaTiO3) on patterned graphene to minimize lateral overgrowth.
- Utilizing high-resolution scanning transmission electron microscopy (STEM) to observe nanometer-scale nuclei.
- Analyzing variations in gallium nitride (GaN) microcrystal array density based on substrate ionicity and graphene layer count.
Main Results:
- Confirmed atomic-scale remote epitaxy through observation of aligned nanometer-scale BaTiO3 nuclei on pinhole-free graphene.
- Demonstrated unique growth cases observable only in remote epitaxy, distinct from other mechanisms.
- Observed macroscopic variations in GaN microcrystal density correlated with substrate ionicity and number of graphene layers.
Conclusions:
- Remote epitaxy is confirmed as an operative atomic-scale growth mechanism.
- The study provides visual and macroscopic evidence distinguishing remote epitaxy.
- Substrate properties significantly influence the outcome of remote epitaxy.
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