Raytheon Company

The University of Arizona

Arizona Board of Regents, a Body Corporate

John Warren Beck

Delmar L Barker

William Owens

Mead M Jordan

Isotopically-enriched graphene and isotope junctions are epitaxially grown on a catalyst substrate using a focused carbon ion beam technique. The focused carbon ion beam is filtered to pass substantially a single ion species including a single desired carbon isotope. The ion beam and filtering together provide a means to selectively isotopically-enrich the epitaxially-grown graphene from given carbon precursor and to selectively deposit graphene enriched with different carbon isotopes in different regions.

Carbon ion beam growth of isotopically-enriched graphene and isotope-junctions

A method of fabricating pillared graphene assembles alternate layers of graphene sheets and fullerenes to form a stable protostructure. Energy is added to the protostructure to break the carbon-carbon bonds at the fullerene-to-graphene attachment points of the protostructure and allow the bonds to reorganize and reform into a stable lower energy unitary pillared graphene nanostructure in which open nanotubes are conjoined between graphene sheets. The attachment points may be functionalized using tether molecules to aid in attachment, and add chemical energy to the system. The arrangement and attachment spacing of the fullerenes may be determined using spacer molecules or an electric potential.

Fabrication of pillared graphene

Carbon nanostructures are synthesized from carbon-excess explosives having a negative oxygen balance. A supercritical fluid provides an environment that safely dissolves and decomposes the explosive molecules into its reactant products including activated C or CO and provides the temperature and pressure for the required collision rate of activated C atoms and CO molecules to form carbon nanostructures such as graphene, fullerenes and nanotubes. The nanostructures may be synthesized without a metal reactant at relatively low temperatures in the supercritical fluid to provide a cost-effective path to bulk fabrication. These nanostructures may be synthesized 'metal free'. As the supercritical fluid provides an inert buffer that does not react with the explosive, the fluid is preserved. Once the nanostructures are removed, the other reaction products may be removed and the fluid recycled.

Carbon nanostructure synthesis from carbon-excess explosives in supercritical fluid

An ion source(s) is configured to generate ions from one or more elements including a plurality of different isotopes or unique molecular combinations of two or more different isotopes from at least one of the selected elements. A selection filter(s) directs a subset of the ions onto a catalytic transmembrane to grow nanotubes of a specific isotope composition on the opposite side of the transmembrane. The nanotubes may be uniformly or selectively doped with dopant atoms. A controller can configure the selection filter(s) to sequentially pass different subsets of ions to form isotope, molecular or element junctions in the growing nanotubes.

Growing community of inventors

Tucson, AZ, United States of America

John Warren Beck