Biomaterial Database

Orientational ordering of the second layer of C60 molecules on Au(111). 2012

Lin Tang, and Quanmin Guo

School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.

We have studied the orientational ordering of the second layer of C(60) molecules on Au(111) using scanning tunnelling microscopy (STM) at 77 K. The orientation of individual molecules within the second layer follows a regular pattern, giving rise to a 2 × 2 superlattice. The long-range order of the 2 × 2 lattice depends on the structure of the first molecular layer with the best ordering found inside the R14° domain. The second layer formed on top of the contrast-disordered R30° domain consists of patches of bright and dim molecules. The contrast between bright and dim patches shows a clear dependence on the sample bias. This bias-dependent contrast is explained by considering the contributions to tunnel current from HOMO and LUMO mediated electron transfer processes. Scanning tunnelling spectroscopic measurement reveals the narrowing of the HOMO-LUMO gap for the layer of molecules in direct contact with the Au(111) substrate.

UI	MeSH Term	Description	Entries
D010316	Particle Size	Relating to the size of solids.	Particle Sizes,Size, Particle,Sizes, Particle
D006046	Gold	A yellow metallic element with the atomic symbol Au, atomic number 79, and atomic weight 197. It is used in jewelry, goldplating of other metals, as currency, and in dental restoration. Many of its clinical applications, such as ANTIRHEUMATIC AGENTS, are in the form of its salts.
D013499	Surface Properties	Characteristics or attributes of the outer boundaries of objects, including molecules.	Properties, Surface,Property, Surface,Surface Property
D016252	Microscopy, Scanning Tunneling	A type of scanning probe microscopy in which a very sharp conducting needle is swept just a few angstroms above the surface of a sample. The tiny tunneling current that flows between the sample and the needle tip is measured, and from this are produced three-dimensional topographs. Due to the poor electron conductivity of most biological samples, thin metal coatings are deposited on the sample.	Scanning Tunneling Microscopy,Scanning Tunnelling Microscopy,Microscopies, Scanning Tunneling,Microscopies, Scanning Tunnelling,Microscopy, Scanning Tunnelling,Scanning Tunneling Microscopies,Scanning Tunnelling Microscopies,Tunneling Microscopies, Scanning,Tunneling Microscopy, Scanning,Tunnelling Microscopies, Scanning,Tunnelling Microscopy, Scanning
D037741	Fullerenes	A polyhedral CARBON structure composed of around 60-80 carbon atoms in pentagon and hexagon configuration. They are named after Buckminster Fuller because of structural resemblance to geodesic domes. Fullerenes can be made in high temperature such as arc discharge in an inert atmosphere.	Buckyballs,Buckminsterfullerenes,Buckminsterfullerene,Buckyball,Fullerene