Novel Graphitic Structures by Design

Graphitic Structures by Design (GSD) is a novel technology for growing graphite in precise patterns from the nano to the macroscale, rapidly (>1 layer/sec), at low temperatures (ca. 500C), and in a single step using ordinary laboratory equipment. The GSD process consists of exposing particular metals (Ni, Pd, Pt, Co), which act as ‘templates’, to a fuel rich combustion environment. As an example, we have thoroughly characterized graphite growth on nickel in a mixture of ethylene and oxygen (O2/C2H4 ratio<3), and found that it grows in a geometry remarkably consistent with the shape of the metal template at a rate of the order one graphene layer/second at temperatures between about 500 and 700C. Graphite structures created with GSD to date include two dimensional ‘screens’ that are inches in extent, yet are composed of micron scale squares graphite foam, hollow nanoparticles , and micron scale particles. All alternative technologies for graphite growth require specialty equipment, such as 2000 C + ovens, and multiple steps. The alternatives are also not suited for a wide variety of pattern growth in either two or three dimensions. We propose to change focus from demonstrating GSD to determination of the mechanism of graphite growth. GSD could meet a number of recognized technological needs for future generation integrated circuits (IC). Precise patterns of oriented graphite are envisioned as: i) replacements of carbon fibers as structural elements in some aerospace and transport applications, ii) as heat conductive pathways aiding thermal management in ICs iii) as electrical conduits in ICs, iv) as the basic elements of nano-scale logic circuits. GSD graphite is arguably superior to the older and more broadly studied carbon nanotubes technology for all these IC applications for many reasons: only GSD be grown in any pattern on any surface, GSD is far cleaner (no metal residue in the graphite structure, in contrast to nanotubes), GSD structures can be formed consistently and cheaply, at low temperature, and only GSD can be readily grown into large designed macrostructures required for some heat transfer applications. INTRODUCTION Graphite is an ‘old’ material, yet surprisingly there are many new ‘high tech’ applications for which graphite in one of its many forms is apparently the best choice. The potential value of new forms of graphite was born out of interest in the new forms it can take, particularly ‘carbon’ (in fact graphite) nanotubes [1]. It is believed that these structures, properly grown and purified, will have unique strength, thermal characteristics and electronic behaviors, and these properties will enable a host of new technologies from space elevators [2] to molecular scale logic circuits [3,4]. Yet nanotubes are simply an elegant nanoscale form of graphite, and most of the ‘special’ properties anticipated for nanotubes can be found in other graphitic structures as well. For this reason designed graphite structures can perform better, or as well as nanotubes in many if not all of technologies suggested for nanotubes. For