Synthesis of Graphene Quantum Dots and Antidots

Abstract

Graphene is a zero-gap semiconductor since the conduction and valence bands meet at the Dirac points and exhibit a linear dispersion. The electronic density of states is zero at the Dirac points. This topology of the bands gives rise to unique and exotic electronic transport properties. The charge carriers are massless, which affects an extreme intrinsic carrier mobility. This makes graphene a promising candidate for applications in high-frequency electronics as a being more suitable than logic-based transistors. While it is clear that outstanding properties of graphene with fascinating electronic structure that received the most attention, this intrinsic character is seen as one of the most challenging in terms of the opening the band gap. Recently, the constricting of graphene into a finite structure has attracted the most intensive research. A great mount of theoretical work demonstrated that the influence of band structure can be varied by edge structure and width. The first experimental results, known as a graphene nanoribbon (GNR), were patterned by electron beam lithography. The measured energy gaps were found to be inversely proportional to GNR width. However, lithographic and graphene etching resolution is limited within the sub-10nm regime. In an attempt to solve these problems, solution processing with chemical reagents was employed to exfoliate the graphite sheets down into a narrower size, which yield GNR with a variety of shapes and repeatable uniformity. Furthermore, graphene nanomesh as a closely related structure to GNRs has been reported

a periodic array of holes in a graphene sheet, with the necks between adjacent holes narrowing to 5nm, which provides the confinement to easily open a band gap. The objective of this dissertation is to mainly introduce the optical properties and their applications of nanostructured graphene

graphene quantum dot (GQD) as a closely related with GNR material, and pseudo-nanomesh fabricated from catalytic etching of metal nanoparticle. The book starts with a broad description of the graphene, which contains the atomic structure of graphene, synthetic methods, characterization using optical tool, and patterning, since these will help a general understanding of the graphene. Once an understanding of the graphene is obtained, we move towards describing each of experiments in Chapter 2 and 3.