CHARGE TRANSPORT STUDIES OF GRAPHENE BASED MOLECULAR TUNNEL JUNCTIONS

Abstract

Central to the development of molecular electronics is the understanding of the charge transport through molecular tunnel junctions. A lack of suitable and reliable platform to perform charge transport studies has constrained both the fundamental understanding and practical applications of molecular electronics. In this thesis, we studied systematically the effects of electronic structure, supramolecular structure, electrode and molecule-electrode interactions on charge transport through molecular tunnel junctions with the EGaIn (eutectic gallium and indium) techniques. Using graphene as the bottom electrode and van der Waal molecule-graphene interactions, we demonstrate a stable molecular electronics platform and clarify that the origin of odd-even effect in charge tunnelling rates is the intrinsic properties of SAMs. By tuning the electronic and supramolecular structures, we show that the electronic characteristics of molecular tunnel junctions can be widely modulated. We also show that weak noncovalent molecule-electrode interactions lead to well-performing molecular diodes on graphene.