Controllable Tunneling Triboelectrification of Two-Dimensional Chemical Vapor Deposited MoS2

He Wang,Chung-Che Huang,Tomas Polcar

doi:10.1038/s41598-018-36830-1

Abstract

Tunneling triboelectrification of chemical vapor deposited monolayer MoS2 has been characterized at nanoscale with contact-mode atomic force microscopy (AFM) and Kelvin force microscopy (KFM). Although charges can be trapped on insulators like SiO2 by conventional triboelectrification, triboelectric charges tunneling through MoS2 and localized at the underlying substrate exhibit more than two orders of magnitude longer lifetime. Their polarity and density can be modified by triboelectric process with various bias voltages applied to Pt-coated AFM tips, and the saturated density is almost 30 times higher than the reported result of SiO2. Thus, the controllable tunneling triboelectric properties of MoS2 on insulating substrates can provide guidance to build a new class of two-dimensional (2D) MoS2-based nanoelectronic devices.

Highlights

Tunneling triboelectrification of chemical vapor deposited monolayer MoS2 has been characterized at nanoscale with contact-mode atomic force microscopy (AFM) and Kelvin force microscopy (KFM)
High-quality 2D MoS2 films were synthesized by chemical vapor deposition (CVD) method
As evident from the surface topography measured by tapping-mode AFM in Fig. 1b, the step height of monolayer MoS2 from substrate is ~0.8 nm, which is consistent with the reported thickness of mechanically exfoliated MoS2 monolayers[33,34,35,36,37,38]

Summary

Introduction

Tunneling triboelectrification of chemical vapor deposited monolayer MoS2 has been characterized at nanoscale with contact-mode atomic force microscopy (AFM) and Kelvin force microscopy (KFM). Charges can be trapped on insulators like SiO2 by conventional triboelectrification, triboelectric charges tunneling through MoS2 and localized at the underlying substrate exhibit more than two orders of magnitude longer lifetime. Their polarity and density can be modified by triboelectric process with various bias voltages applied to Pt-coated AFM tips, and the saturated density is almost 30 times higher than the reported result of SiO2. As 2D materials exhibit high charge density[29], it is of great essence to investigate the triboelectric properties of single-layer MoS2, so that the results can lay the foundation for its applications in triboelectric nanodevices.

Methods

Results

Conclusion