Paper BI-TuP15
Nanoscale Topographical Control of Graphene Architecture by Replication of DNA Nanostructures

Tuesday, October 29, 2013, 6:00 pm, Room Hall B

Graphene is a very fascinating material because of its unique mechanical and electronic properties. One of the major challenges for graphene is to control its electronic structure in a designed manner for various device applications. To control the electronic structure and unit size of graphene nanostructures, various approaches have been reported, including fabrication of graphene nanoribbons, chemical functionalization of graphene, control of strain applied to graphene by stretching or bending and nanoscale control of three-dimensional (3D) topography of graphene. Among these, the 3D topographical control of graphene showed interesting phenomena such as a pseudo-magnetic field, which was observed in 3D strained graphene on Pt nanobubbles by scanning tunneling microscopy. The 3D topographical control of graphene at the nanoscale level is quite difficult because graphene intrinsically prefers a two-dimensional (2D) structure. Although graphene with local 3D topography was reported to exist in the form of nanobubbles on a Pt (111) surface, ripples on CVD graphene, and corrugated structures on double strand deoxyribonucleic acids (ds-DNAs), there are limits to the geometrical shapes that can be constructed.

It is not possible for graphene itself to produce the designed 3D structures except by creating artificial defects in graphene. Designed templates with nanometer-scale precision are thus required to make various 3D graphene structures in a controlled manner. DNA nanotechnology has provided a platform to construct artificially designed nanostructures which were self-assembled with precisely controllable and programmable nanoscale features with the aid of oligonucleotide recognition. Here, we demonstrate that the nanoscale 3D topography of graphene can be controlled in a designed manner by using artificially designed DNA nanostructures with a high degree of geometrical freedom. Two DNA nanostructures, a one-dimensional (1D), five-helix ribbon (5HR) structure and a 2D double-crossover (DX) lattice, were self-assembled in a solution during annealing. After formation of DNA nanostructures, the samples were deposited on a mica surface. CVD graphene, which was grown on a Cu foil, was transferred onto the DNA nanostructures on the mica surface; during this process, graphene nanostructures were successfully replicated from DNA nanostructures. After the successful production of the designed 3D topography of graphene replicated from DNA nanostructures, we further studied its thermal stability. The influence of temperature on its topography and electrical properties was verified by atomic force microscopy (AFM) and a four point probe, respectively.