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Approaching the Schottky-Mott limit in van der Waals metal-semiconductor junctions.

Authors
  • Liu, Yuan1, 2
  • Guo, Jian1
  • Zhu, Enbo1
  • Liao, Lei2
  • Lee, Sung-Joon1
  • Ding, Mengning1
  • Shakir, Imran3
  • Gambin, Vincent4
  • Huang, Yu5, 6
  • Duan, Xiangfeng7, 8
  • 1 Department of Materials Science and Engineering, University of California, Los Angeles, CA, USA.
  • 2 State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and School of Physics and Electronics, Hunan University, Changsha, China. , (China)
  • 3 Sustainable Energy Technologies Centre, College of Engineering, King Saud University, Riyadh, Saudi Arabia. , (Saudi Arabia)
  • 4 NG NEXT, Northrop Grumman Corporation, Redondo Beach, CA, USA.
  • 5 Department of Materials Science and Engineering, University of California, Los Angeles, CA, USA. [email protected]
  • 6 California Nanosystems Institute, University of California, Los Angeles, CA, USA. [email protected]
  • 7 California Nanosystems Institute, University of California, Los Angeles, CA, USA. [email protected]
  • 8 Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA. [email protected]
Type
Published Article
Journal
Nature
Publisher
Springer Nature
Publication Date
May 01, 2018
Volume
557
Issue
7707
Pages
696–700
Identifiers
DOI: 10.1038/s41586-018-0129-8
PMID: 29769729
Source
Medline
License
Unknown

Abstract

The junctions formed at the contact between metallic electrodes and semiconductor materials are crucial components of electronic and optoelectronic devices 1 . Metal-semiconductor junctions are characterized by an energy barrier known as the Schottky barrier, whose height can, in the ideal case, be predicted by the Schottky-Mott rule2-4 on the basis of the relative alignment of energy levels. Such ideal physics has rarely been experimentally realized, however, because of the inevitable chemical disorder and Fermi-level pinning at typical metal-semiconductor interfaces2,5-12. Here we report the creation of van der Waals metal-semiconductor junctions in which atomically flat metal thin films are laminated onto two-dimensional semiconductors without direct chemical bonding, creating an interface that is essentially free from chemical disorder and Fermi-level pinning. The Schottky barrier height, which approaches the Schottky-Mott limit, is dictated by the work function of the metal and is thus highly tunable. By transferring metal films (silver or platinum) with a work function that matches the conduction band or valence band edges of molybdenum sulfide, we achieve transistors with a two-terminal electron mobility at room temperature of 260 centimetres squared per volt per second and a hole mobility of 175 centimetres squared per volt per second. Furthermore, by using asymmetric contact pairs with different work functions, we demonstrate a silver/molybdenum sulfide/platinum photodiode with an open-circuit voltage of 1.02 volts. Our study not only experimentally validates the fundamental limit of ideal metal-semiconductor junctions but also defines a highly efficient and damage-free strategy for metal integration that could be used in high-performance electronics and optoelectronics.

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