Effect of flexoelectricity on a bilayer molybdenum disulfide Schottky contact

authored by: Liang Sun, B. Javvaji, Chunli Zhang, Xiaoying Zhuang, Weiqiu Chen
Abstract: Molybdenum disulfide (MoS₂), as a representative two-dimensional material, has distinctive physical and mechanical properties, especially in a bilayer form. Here, we conduct a study on the effect of out-of-plane flexoelectricity on a fabricated bilayer MoS₂ Schottky contact via the Conductive Atomic Force Microscope (CAFM). The induced polarization in the sample under the tip force, which is entirely from the flexoelectric mechanism due to the absence of out-of-plane piezoelectricity in terms of the molybdenum-to-sulfur bond symmetry, changes the barrier height of the formed Schottky contact between the bilayer MoS₂ and Au electrode. According to the Hertzian contact theory and the modified current equation of the classical thermionic emission theory, the relationship between the strain gradient and the effective barrier height ϕ_Bp is quantitatively presented. The out-of-plane flexoelectric coefficients of the bilayer MoS₂ are thus evaluated as f₃₃₃₃=0.4758 nC/m and f₃₁₁₃=f₃₂₂₃=0.2867 nC/m.
Organisation(s): Institute of Photonics
External Organisation(s): Zhejiang University
Type: Article
Journal: NANO ENERGY
Volume: 102
ISSN: 2211-2855
Publication date: 11.2022
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, General Materials Science, Electrical and Electronic Engineering
Sustainable Development Goals: SDG 7 - Affordable and Clean Energy
Electronic version(s): https://doi.org/10.1016/j.nanoen.2022.107701 (Access: Closed)