Electronic Transport in Strained Graphene

Graphene is a single atomic layer material with exceptional electronic and mechanical properties. Graphene has formed the basis of many nanoelectromechanical and strain sensing devices. However, the ultimate limit of miniaturization of such sensors has not yet been ascertained. In this work we present the fabrication and electrical characterization of nanoscale pressure sensors realized from suspended graphene membrane devices.We start in chapter 1 by describing the elemental electronic properties of graphene. Followed by the motivation of the origin of the particular geometry used in our pressure sensors. Chapter 2 describes in detail the fabrication techniques required to make the graphene devices. In chapter 3 we show the room temperature electrical transport of our devices and find that the injected current division between counter electrodes depends on pressure and can be used to realize a nanoscale pressure sensor. Estimating various potential contributions to the resistivity change of the deflected graphene membrane including piezoresistivity, changing gate capacitance, and the valley Hall effect due to the pressure-induced synthetic magnetic field, we find that the valley Hall effect yields the largest expected contribution to the longitudinal resistivity modulation for accessible device parameters. Chapter 4 shows the electronic transport at low temperatures. We find conductance fluctuations as a function of gate voltage. Finally we conclude with a brief summary and potential research outlook