Schottky-barrier-free contacts with two-dimensional semiconductors by surface-engineered MXenes
Abstract
Two-dimensional (2D) metal carbides and nitrides, called MXenes, have attracted great interest for applications such as energy storage. Here we demonstrate their potential as Schottky-barrier-free metal contacts to 2D semiconductors, providing a solution to the contact-resistance problem in 2D electronics. Based on first principles calculations, we find that the surface chemistry strongly affects the Fermi level of MXenes: O termination always increases the work function with respect to that of bare surface, OH always decreases it, while F exhibits either trend depending on the specific material. This phenomenon originates from the effect of surface dipoles, which together with the weak Fermi level pinning, enable Schottky-barrier-free hole (or electron) injection into 2D semiconductors through van der Waals junctions with some of the O-terminated (or all the OH-terminated) MXenes. Furthermore, we suggest synthetic routes to control the surface terminations based on the calculated formation energies. This study enhances the understanding of the correlation between surface chemistry and electronic/transport properties of 2D materials, and also gives practical predictions for improving 2D electronics.
Additional Information
© 2016 American Chemical Society. Received: October 17, 2016; Published: November 22, 2016. Y.L. thanks the support from Resnick Prize Postdoctoral Fellowship at Caltech. This research was funded by DOE DESC0014607. This work used computational resources sponsored by the DOE's Office of Energy Efficiency and Renewable Energy and located at the National Renewable Energy Laboratory; the Extreme Science and Engineering Discovery Environment (XSEDE; supported by NSF Grant ACI-1053575); and the National Energy Research Scientific Computing Center (NERSC; a DOE Office of Science User Facility supported by the Office of Science of the U.S. DOE under Contract DE-AC02-05CH11231). The authors declare no competing financial interests.Attached Files
Supplemental Material - ja6b10834_si_001.pdf
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Additional details
- Eprint ID
- 72275
- Resolver ID
- CaltechAUTHORS:20161123-091514649
- Resnick Sustainability Institute
- Department of Energy (DOE)
- DE-SC0014607
- NSF
- ACI-1053575
- Department of Energy (DOE)
- DE-AC02-05CH11231
- Created
-
2016-11-23Created from EPrint's datestamp field
- Updated
-
2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute, JCAP