Abstract

The high field phenomena of inter-valley transfer and avalanching breakdown have long been exploited in devices based on conventional semiconductors. In this Article, we demonstrate the manifestation of these effects in atomically-thin WS2 field-effect transistors. The negative differential conductance exhibits all of the features familiar from discussions of this phenomenon in bulk semiconductors, including hysteresis in the transistor characteristics and increased noise that is indicative of travelling high-field domains. It is also found to be sensitive to thermal annealing, a result that we attribute to the influence of strain on the energy separation of the different valleys involved in hot-electron transfer. This idea is supported by the results of ensemble Monte Carlo simulations, which highlight the sensitivity of the negative differential conductance to the equilibrium populations of the different valleys. At high drain currents (>10 μA/μm) avalanching breakdown is also observed, and is attributed to trap-assisted inverse Auger scattering. This mechanism is not normally relevant in conventional semiconductors, but is possible in WS2 due to the narrow width of its energy bands. The various results presented here suggest that WS2 exhibits strong potential for use in hot-electron devices, including compact high-frequency sources and photonic detectors.

Details

Title
Negative Differential Conductance & Hot-Carrier Avalanching in Monolayer WS2 FETs
Author
G He 1 ; Nathawat, J 1   VIAFID ORCID Logo  ; C-P, Kwan 2 ; Ramamoorthy, H 1 ; Somphonsane, R 3 ; Zhao, M 4 ; Ghosh, K 1 ; Singisetti, U 1 ; Perea-López, N 5 ; Zhou, C 6 ; Elías, A L 5 ; Terrones, M 7 ; Gong, Y 8 ; Zhang, X 8 ; Vajtai, R 8   VIAFID ORCID Logo  ; Ajayan, P M 8 ; Ferry, D K 9 ; Bird, J P 1   VIAFID ORCID Logo 

 1Department of Electrical Engineering, University at Buffalo, the State University of New York, Buffalo, NY, USA 
 Department of Physics, University at Buffalo, the State University of New York, Buffalo, NY, USA 
 Department of Physics, King Mongkut’ s Institute of Technology Ladkrabang, Bangkok, Thailand 
 High-Frequency High-Voltage Device and Integrated Circuits Center, Institute of Microelectronics of Chinese Academy of Sciences, 3 Beitucheng West Road, Chaoyang District, Beijing, PR China 
 Department of Physics and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania, USA 
 Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania, USA 
 Department of Physics and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Chemistry and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania, USA 
 Department of Materials Science and Nano Engineering, Rice University, Houston, TX, USA 
 School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona, USA 
Pages
1-9
Publication year
2017
Publication date
Sep 2017
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1954329869
Copyright
© 2017. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.