Graphene separation and stretching induced by piezoelectric effect of ferroelectric domains: impact on the conductance of graphene channel

TL;DR

This paper explores how the piezoelectric effect of ferroelectric domains influences graphene separation and conductance, revealing a novel mechanism for controlling graphene-based electronic devices without extra fabrication steps.

Contribution

It introduces a new understanding of how ferroelectric domain-induced piezoelectric effects can modulate graphene conductance and enable suspended graphene fabrication.

Findings

Graphene separation occurs at ferroelectric domain walls due to piezoelectric displacement.

Conductance of graphene increases with domain wall-induced stretching, affecting electron scattering.

Proposes a method for fabricating suspended graphene using ferroelectric substrate piezo-effects.

Abstract

P-N junctions in graphene on ferroelectric have been actively studied, but the impact of piezoelectric effect in ferroelectric substrate with ferroelectric domain walls (FDWs) on graphene characteristics was not considered. Due to the piezo-effect ferroelectric domain stripes with opposite spontaneous polarizations elongate or contract depending on the polarity of voltage applied to the substrate. We show that the alternating piezoelectric displacement of the ferroelectric domain surfaces can lead to the alternate stretching and separation of graphene areas at the steps between elongated and contracted domains. Graphene separation at FDWs induced by piezo-effect can cause unusual effects. In particular, the conductance of graphene channel in a field effect transistor increases essentially, because electrons in the stretched section scatter on acoustic phonons. At the same time the graphene conductance is determined by ferroelectric spontaneous polarization and varies greatly in the presence of FDWs. The revealed piezo-mechanism of graphene conductance control is promising for next generations of graphene-based field effect transistors, modulators, electrical transducers and piezo-resistive elements. Also our results propose the method of suspended graphene fabrication based on piezo-effect in a ferroelectric substrate that does not require any additional technological procedures.