Enabling Chemistry to Realize Quantum Confinement Effect in Graphene

초록

Scientific and technological interest in graphene has rapidly grown due to its outstanding physical and electronic properties. To fully realize its technological potential, it is crucial to understand how to create a band gap as graphene is a semimetal as it does not have a technologically relevant band gap. It has been shown that sub-20 nm patterning can be used to open up a band gap in graphene through the quantum confinement effect. We will discuss approaches for creating semiconducting nanoperforated graphene and graphene nanoribbons using block copolymers, which addresses all of the following challenges simultaneously: (i) scalability, (ii) compatibility with the current manufacturing processes, (iii) high resolution, and (iv) pattern fidelity. Block copolymer (BCP) thin films with directed orientation of the microdomains can be achieved by surface modification to tune the interfacial energies. To do so, functional random copolymers can be used as a platform to modify surface, where the surface modifying copolymer is capable of anchoring via side groups to an oxide surface or crosslinking with itself. The relationship between the composition of the copolymer, the composition of the overlying BCP equilibrated on these surfaces and the resulting morphology will be discussed. By developing the materials and processes for the fabrication of sub-20 nm features over large areas, we study the structure-property relationships in nanopatterned graphene as a function of constriction width. Finally, we will discuss rational approaches to achieve smaller critical dimension for higher band gap in graphene by designing new block copolymers which can phase-separate at lower degree of polymerization.