AUSTRALIA - JAPAN SYMPOSIUM

AUSTRALIA - JAPAN SYMPOSIUM ON EARTH SYSTEMS SCIENCE
AND ON NANOMATERIALS

Canberra, 21 November 2006

Electrical conduction in low-dimensional nanostructures for novel nanoelectronic devices
Professor Masakazu Aono, Nano System Functionality Center, National Institute for Materials Science (NIMS), Japan

Masakazu Aono received his PhD from the University of Tokyo in 1972. He has served as a researcher (1972- 1976) and senior researcher (1976-1986) at National Institute for Research in Inorganic Materials (NIRIM), chief scientist at Institute for Physical and Chemical Research (RIKEN) (1986-2002), and professor at Osaka University (1996-2004). He is now a fellow and the coordinating director of Key Nanotechnologies Field and the directorgeneral of Nano System Functionality Center, National Institute for Materials Science (NIMS). His main research interests lie in nanoscience and technology, nanoelectronics, and surface science.

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The electrical conduction in low-dimensional nanostructures is of essential importance in designing novel nanoelectronic devices. In particular, diffusive conduction at the ~100 nm scale and ballistic (quantized) conduction at the ~10 nm scale are of central importance with respect to most nanoelectronic devices. Solitonic and polaronic conduction in polymer nanowires also attracts great attention in relation to molecular nanoelectronic devices.

Here ballistic, diffusive, and polaronic electrical conduction regimes observed by multiprobe scanning tunneling microscopes (MPSTMs) and related methods are discussed for the following organic and inorganic nanostructures:

  • Single-wall carbon nanotubes
  • Erbium disilicide (ErSi2) nanowires
  • Single polydiacetylene molecular wires
  • Short chains of chemically-bonded fullerene molecules (C60)
  • Point contacts formed by metal atom bridging

The electron mean free path was measured to be ~470 nm for single-wall carbon nanotubes and ~25 nm for ErSi2 nanowires. By injecting a high density of electrons or holes into single polydiacetylene molecular wires, the molecular wires were changed to a metallic state. A novel molecular switch using local reversible polymerization and depolymerization of C60 molecules was created.