Band gap tuning of Ge/SiC bilayers under an electric field: a density functional study


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Abstract

The structure and electronic properties of Ge/SiC van der Waals (vdW) bilayer under the influence of an electric field have been investigated by the first-principles method. Without an electric field, the system shows a small band gap of 126 meV at the equilibrium state. Interestingly, by applying a vertical external electric field, the results present a parabola-like relationship between the band gap and the strength. As the negative E-field changes from 0.0 to −0.40 V/Å, the band gap first increases to a maximum of about 378 meV and then decreases to zero. A similar trend is exhibited for the positive E-field, ranging from 0.0 to +0.40 V/Å. The band gap reaches a maximum of about 315 meV at +0.10 V/Å. The significant variations of band gap are owing to different states of Ge, Si, and C atoms in conduction band and valence band. The predicted electric field tunable band gap of the Ge/SiC vdW heterostructures is very promising for its potential use in nanodevices.

About the authors

M. Luo

Department of Physics

Author for correspondence.
Email: mluo2011@gmail.com
China, Shanghai, 201209

Y. E. Xu

Department of Electronic Engineering

Email: mluo2011@gmail.com
China, Shanghai, 201306

Y. X. Song

Key Laboratory of Polar Materials and Devices

Email: mluo2011@gmail.com
China, Shanghai, 200241

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