Evidence of Nanocrystalline Semiconducting Graphene Monoxide during Thermal Reduction of Graphene Oxide in Vacuum

• Published in: ACS nano 2011-12, Vol.5 (12), p.9710-9717
• Main Authors: Mattson, Eric C, Pu, Haihui, Cui, Shumao, Schofield, Marvin A, Rhim, Sonny, Lu, Ganhua, Nasse, Michael J, Ruoff, Rodney S, Weinert, Michael, Gajdardziska-Josifovska, Marija, Chen, Junhong, Hirschmugl, Carol J
• Format: Article
• Language: English
• Subjects: Crystallization - methods; Electric Conductivity; Electronics; Graphene; Graphite - chemistry; Hot Temperature; Macromolecular Substances - chemistry; Materials Testing; Molecular Conformation; Nanocrystals; Nanostructure; Nanostructures - chemistry; Nanostructures - ultrastructure; Oxidation-Reduction; Oxides; Oxides - chemistry; Particle Size; Segregations; Semiconductors; Surface Properties; Tuning; Unit cell; Vacuum
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/nn203160n

As silicon-based electronics are reaching the nanosize limits of the semiconductor roadmap, carbon-based nanoelectronics has become a rapidly growing field, with great interest in tuning the properties of carbon-based materials. Chemical functionalization is a proposed route, but syntheses of graphene oxide (G-O) produce disordered, nonstoichiometric materials with poor electronic properties. We report synthesis of an ordered, stoichiometric, solid-state carbon oxide that has never been observed in nature and coexists with graphene. Formation of this material, graphene monoxide (GMO), is achieved by annealing multilayered G-O. Our results indicate that the resulting thermally reduced G-O (TRG-O) consists of a two-dimensional nanocrystalline phase segregation: unoxidized graphitic regions are separated from highly oxidized regions of GMO. GMO has a quasi-hexagonal unit cell, an unusually high 1:1 O:C ratio, and a calculated direct band gap of ∼0.9 eV.