Edge-induced Schottky barrier modulation at metal contacts to exfoliated molybdenum disulfide flakes
- Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, Sakai 599-8570 (Japan)
Ultrathin two-dimensional semiconductors obtained from layered transition-metal dichalcogenides such as molybdenum disulfide (MoS{sub 2}) are promising for ultimately scaled transistors beyond Si. Although the shortening of the semiconductor channel is widely studied, the narrowing of the channel, which should also be important for scaling down the transistor, has been examined to a lesser degree thus far. In this study, the impact of narrowing on mechanically exfoliated MoS{sub 2} flakes was investigated according to the channel-width-dependent Schottky barrier heights at Cr/Au contacts. Narrower channels were found to possess a higher Schottky barrier height, which is ascribed to the edge-induced band bending in MoS{sub 2}. The higher barrier heights degrade the transistor performance as a higher electrode-contact resistance. Theoretical analyses based on Poisson's equation showed that the edge-induced effect can be alleviated by a high dopant impurity concentration, but this strategy should be limited to channel widths of roughly 0.7 μm because of the impurity-induced charge-carrier mobility degradation. Therefore, proper termination of the dangling bonds at the edges should be necessary for aggressive scaling with layered semiconductors.
- OSTI ID:
- 22597669
- Journal Information:
- Journal of Applied Physics, Vol. 120, Issue 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
BENDING
CARRIER MOBILITY
CHARGE CARRIERS
CONCENTRATION RATIO
DOPED MATERIALS
ELECTRODES
IMPURITIES
MODULATION
MOLYBDENUM
MOLYBDENUM SULFIDES
POISSON EQUATION
SCALING
SCHOTTKY BARRIER DIODES
SEMICONDUCTOR MATERIALS
SILICON OXIDES
TRANSISTORS
TWO-DIMENSIONAL CALCULATIONS
WIDTH