Photo response of multi-layer graphene sheet and nanoribbons

A advanced plasma chemical vapor deposition (CVD) method has outstanding advantages for the structural-controlled growth and damage-free functionalization of nano carbon materials such as carbon nanotubes (CNTs) and graphene. Graphene nanoribbons combine the unique electronic and spin properties of graphene with a transport gap that arises from quantum confinement and edge effects. This makes them an attractive candidate material for the channels of next-generation transistors. Nanoribbons can be made in a variety of ways, including lithographic, chemical and sonochemical approaches, the unzipping of carbon nanotubes, the thermal decomposition of SiC and organic synthesis. However, the reliable site and alignment control of nanoribbons with high on/off current ratios remains a challenge. We have developed a new, simple, scalable method based on the advanced plasma CVD method for directly fabricating narrow (~23 nm) graphene nanoribbon devices with a clear transport gap (58.5 meV) and a high on/off ratio (>104). Since the establishment of our novel graphene nanoribbon fabrication method, direct conversion of a Ni nanobar to a graphene nanoribbon is now possible. Indeed, graphene nanoribbons can be grown at any desired position on an insulating substrate without any post-growth treatment, and large-scale, twoand three dimensional integration of graphene nanoribbon devices should be realizable, thereby accelerating the practical evolution of graphene nanoribbon-based electrical applications.