Fabrication of Graphene-based Devices by Local Anodic Oxidation using an Atomic Force Microscopy based Robotic Platform

Graphene, a two-dimensional hexagonal carbon lattice structure, has attracted increasing attention as a novel material for high-performance nanoscale devices because of its extraordinary properties such as high charge carrier mobility and unique band structure. The electrical properties of graphene structures are strongly affected by their atomic configuration and therefore, precise control of graphene geometries, orientation and positioning is critical in the fabrication of graphene based devices. However, traditional nanofabrication techniques such as electron beam lithography are difficult to accomplish the control of graphene structures at atomic resolution.The objective of the proposed research is to develop an integrated solution to image and pattern graphene with desired structures and properties, within a single platform. By leveraging the atomic force microscopy (AFM) based high-resolution characterization, mechanical manipulation and dissection along with Local Anodic Oxidation (LAO) techniques, a robotic platform will be developed, which enables atomic resolution imaging, precise manipulation, patterning and etching, as well as electrical characterization of the graphene structures. In order to accomplish the goal, we will address several issues: 1) achieve the atomic resolution imaging for detailed characterization and determination of the graphene lattice structures; 2) develop the AFM system and the force/position control strategy for precise manipulation and dissection of graphene structures by AFM probes, and integrate the LAO process into the mechanical dissection for patterning and etching of graphene structures. Specific geometry of graphene nanoribbons with width in the nanometer range can be obtained by controlling the cutting direction along specific lattice orientation; 3) understand and exploit the model governing graphene nanoribbons formation during the dissection process, to determine the effect of input voltage, cutting force and direction on the resulting geometry of graphene structures; 4) investigate the electrical properties of the graphene structures after manipulation and patterning and correlate the experimental findings to the theoretical electronic band structure model.Unlike other traditional cumbersome fabrication approaches with limited reproducibility, the new system provides an effective approach for fabrication of functional nano devices based on specific graphene structures with the desired electrical properties. Ultimately, the proposed fabrication platform can be further developed for automated manufacturing of graphene based devices. The results of the proposed research will not only create new knowledge and multi-disciplinary insights, but also overcome the hurdle in the fabrication of graphene based devices for a wide range of emerging applications including sensors, transistors, solar cells and display.