The density functional theory calculations with local density approximation have been performed to simulate scanning tunneling microscopy (STM) images of individual molecules in close-packed upright alkanthiol self-assembled monolayers (SAMs) on Au(111) surface. The internal patterns in the simulated STM images are dependent on bias voltage and alkanethiol chain length, and have characteristic of the topographic effect modulated by the electronic effect. The electronic structure of the adsorption system is analyzed for discussing STM imaging mechanism of alkanethiol SAMs. Besides enhancing the intermixing between alkyl part and Au substrate states, sulfur atom in alkanethiol obviously influences the pattern in STM image by its chemisorption mode on Au(111) surface. Simulated images qualitatively reproduce STM experimental results.
C60 molecule have become increasingly important during the last decade concerning both their basic physical and chemical properties as well as potential applications. Explorations of C60 based nano-devices have been performed recently based on the unique properties of C60 molecules. In this paper, the transport properties of C60 single molecules in different tunneling junction configurations are reported and a summary of the theoretical and experimental development of C60 based molecular device is presented and discussed.
Conference Committee Involvement (1)
19 May 2003 | Maspalomas, Gran Canaria, Canary Islands, Spain