Nanoscale mapping of dielectric properties based on surface adhesion force measurements

Ying Wang,Xingya Wang,Bin Li,Zhiwei Shen,Yi Zhang,Jun Hu,Yue Shen

doi:10.3762/bjnano.9.84

Abstract

The detection of local dielectric properties is of great importance in a wide variety of scientific studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion forces. Thus, GO and RGO could be conveniently differentiated. This method provides a simple and general approach for the fast characterization of the local dielectric properties of graphene-based materials and will further facilitate their applications in energy generation and storage devices.

Highlights

The local dielectric distribution is a key factor that influences the physical properties and functionalities of various materials such as polymer nanocomposites [1,2,3,4], carbon nanotube compounds [5,6,7,8], metal–dielectric films [9,10,11,12], and biomembranes [13,14,15]
We propose that fast mapping of the local dielectric distribution on a sample surface can be achieved with high lateral resolution by combining the advantages of the electrowetting (EW) effect [33] and an Atomic force microscopy (AFM) imaging mode, PeakForce Quantitative Nano-Mechanics (PF-QNM) [34]
The apparent height of the CRGO sheet under the biased AFM tip changed very little, which is quite different from the result in our previous SPFM experiment, in which the apparent height of reduced graphene oxide (RGO) sheets under a biased tip usually increased sharply when RH was lower than 40% [32]

Summary

Introduction

The local dielectric distribution is a key factor that influences the physical properties and functionalities of various materials such as polymer nanocomposites [1,2,3,4], carbon nanotube compounds [5,6,7,8], metal–dielectric films [9,10,11,12], and biomembranes [13,14,15]. We propose that fast mapping of the local dielectric distribution on a sample surface can be achieved with high lateral resolution by combining the advantages of the electrowetting (EW) effect [33] and an AFM imaging mode, PeakForce Quantitative Nano-Mechanics (PF-QNM) [34].

Results

Conclusion