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Thursday, 30 August 2012

Graphene nanoislands made to order

Reporting in Nano Letters, a team led by ICN Division Leader Gustavo Ceballos describes a new method for selective epitaxial growth of graphene nanostructures on nickel.

The team achieved selective epitaxial growth of triangular and hexagonal graphene nanoislands from 1 to 300 nm2 in surface area, via decomposition of propene on a single-crystal nickel surface. The process enables an unprecedented level of control over the size and shape of graphene nanostructures and provides excellent edge-quality.

PhD student Marc Ollé, colleagues from ICN's Atomic Manipulation and Spectroscopy Group and ICN's Nanoscience Instrument Development Division, and Dr David Serrate from INA-LMA at the University of Zaragoza have just published an article in Nano Letters, entitled "Yield and shape selection of graphene nanoislands grown on Ni(111)", in which they report a new, highly-selective method for fabrication of graphene nanostructures of excellent quality.

 

Graphene, often heralded as "the material of the future" due to its impressive mechanical, optical and electrical characteristics, is a staple of basic Nanoscience research and has myriad applications in Nanotechnology. Many of these applications are directly related to the size and shape of graphene nanostructures and to the homogeneity of their edges. Thus, there is pressing academic and industrial demand for controlled fabrication of graphene nanostructures. However, current nanofabrication methods are rather limited in terms of control over the size and shape of the desired structure, and often provide poor edge-quality.

To create their nanoislands, the team harnessed epitaxial growth, a process typically used to create flat graphene sheets, whereby a graphene layer is gradually assembled by reacting a hydrocarbon directly on a crystalline metallic template. They gradually decomposed propene on a single-crystal nickel surface under ultra-high vacuum to generate triangular and hexagonal graphene nanoislands with a surface area of 10 to 300 nm2 and with high-quality, zigzag edges. They studied the growth process by Scanning Tunnelling Microscopy (STM), and were able to control the size and shape of the nanoislands by modulating reaction parameters including the propene dose, the temperature and the post-annealing procedure.

The resulting nanostructures, and the growth process itself, should find diverse applications where controlled fabrication of tiny graphene sheets is needed.

The article, "Yield and shape selection of graphene nanoislands grown on Ni(111)", can be accessed here.