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| VOLUME 105 (2017) | ISSUE 2 | PAGE 105 |
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Modulation of band gap by normal strain and an applied electric field in SiC-based heterostructures1)
M. Luo+ 2), Y. E. Xu+*, Y. X. Song×
+Department of Electronic Engineering, Shang Hai Jian Qiao University, 201306 Shanghai, China *School of Microelectronic of Fudan University, 200433 Shanghai, China ×Key Laboratory of Polar Materials and Devices, East China Normal University, 200241 Shanghai, China
Abstract
The structure and electronic properties of the WS2/SiC van der Waals (vdW) heterostructures under the influence of normal strain and an external electric field have been investigated by the first-principles method. Our results reveal that the compressive strain has much influence on the band gap of the vdW heterostructures and the band gap monotonically increases from 1.330 to 1.629 eV. The results also imply that electrons are likely to transfer from WS2 to SiC monolayer due to the deeper potential of SiC monolayer. Interestingly, by applying a vertical external electric field, the results present a parabola-like relationship between the band gap and the strength. As the E-field changes from -0.50 to +0.20 V/Å, the band gap first increases from zero to a maximum of about 1.90 eV and then decreases to Zero. The significant variations of band gap are owing to different states of W, S, Si, and C atoms in conduction band and valence band. The predicted electric field tunable band gap of the WS2/SiC vdW heterostructures is very promising for its potential use in nanodevices. |