1.1Organization of nanostructure science and technology and the WTEC study.

2.1 Schematic of variety of nanostructure synthesis and assembly approaches.
2.2 Interactive cycle of characterization, understanding and enhanced control in the synthesis and assembly of nanostructures.
2.3 TEM images of (a) the lamellar morphology, (b) the cubic phase with Ia3d symmetry viewed along its [111] zone axis, and (c) the hexagonal phase viewed along its [001] zone axis of thesilica/surfactant nanostructured composites by co-assembly (McGehee et al. 1994) (bars = 30 nm).
2.4 TEM image of unlinked cluster array of 3.7 nm Au clusters encapsulated by dodecanethiol (Andres et al. 1998).
2.5 Array of InAs quantum dot structures grown on GaAs substrates (Mirin et al. 1996).
2.6 Variation of optical transparency with diameter of chemically synthesized CdSe nanocrystals (Alivisatos 1996).
2.7 A sequence of 670 nm by 670 nm AFM images taken during the manipulation of a 50 nm Au particle into the gap between two Au/Ti electrodes (Junno et al. 1998).

3.1 Transparency as a function of particle size (courtesy, Nanophase).

4.1 Schematic drawing of the experimental setup used in Göteborg for studies of chemical reactivity and/or sticking probability of various molecules with the clusters. The production of clusters is via laser vaporization of metal substrates and detection via photo-ionization time-of-flight mass spectrometry. (A. Rosen, University of Göteborg, Sweden.)
4.2 Effect of moisture on conversion profiles for CO oxidation over Co3O4 and Au/Co3O4.
4.3 Hydrodesulfurization reaction. Selective catalysis is controlled by either the edge or rim of MoS2. (Chianelli 1998).
4.4 Hydrogen absorption-desorption characteristics for mixture of Mg and Mg2Ni prepared by mechanical alloying.
4.5 Typical zeolite structures together depicting the positions of the O atoms (vertices in upper figure) and two different zeolitic structures one (a) with a three dimensional structure and (b) a zeolite with a two dimensional channel structure.
4.6 Examples of carbon nanotube structures, including multiwalled and metal-atom-filled nanotubes.

5.1 Functional device scales.
5.2 Metal colloids, self-assembled monolayer (SAM) coatings, polysilicon, quantum dots embedded in SiO2 (Hitachi, IBM, RIKEN, NTT, ETL, University of Lund).
5.3 Sidewall extensions of MOSFET gate (Toshiba).
5.4 Oxidation of metal or semiconductor with scanning tunneling microscope (STM) tip (ETL).
5.5 STM probe oxidation of metal on vicinal substrate steps (ETL).
5.6 Double barrier tunnel diode structure (Max-Planck-Institut, Stuttgart; NTT).
5.7 Gated double barrier tunnel diode structure (Max-Planck-Institut, Stuttgart; NTT; Purdue University).
5.8 Depletion layer control of 2DEG area (Hitachi, University of Glasgow, University of Tokyo).
5.9 Tetrahedral shaped recess, TSR (Fujitsu).
5.10 Double barrier metallic SET patterned by e-beam (NEC).
5.11 A single molecule connecting metallic contacts (Yale University, University of South Carolina, Delft University, Karlsruhe University).
5.12 Granular GMR-Co, Fe (Nagoya University, Tohoku University, CNRS-Thomson, UCSB, UCSD).
5.13 Current in plane (Matsushita, Fujitsu, Mitsubishi, Toshiba, Hitachi, Thomson, Philips, Siemens, IBM, Univ. Regensburg, IMEC, Nagoya University, Tohoku University, NIST).
5.14 Magnetic tunnel junction (IBM, MIT, HP, Tohoku University).
5.15 Ferromagnetic/metal/ferromagnetic: 3 - 60 periods free-standing (NRL, CNRS-Thomson, Philips, Michigan State, Lawrence Livermore Labs); plated into pores (L'École Polytechnique Fédérale de Lausanne, Johns Hopkins University, Université Catholique Louven).
5.16 Schematic of a semiconductor laser.
5.17 Density of electronic states as a function of structure size.

6.1 Ratio of the Young's (E) and shear (G) moduli of nanocrystalline materials to those of conventional grain size materials as a function of grain size. The dashed and solid curves correspond to a grain boundary thickness of 0.5 and 1 nm, respectively (Shen et al. 1995).
6.2 Elongation to failure in tension vs. grain size for some nanocrystalline metals and alloys.
6.3 Effective permeability, µe , vs. saturation magnetic flux density, Bs , for soft ferromagnetic materials (after A. Inoue 1997).

7.1 Organization of the WTEC study; sections with large biological content are indicated.
7.2 Top: a 36-mer protein polymer with the repeat sequence (ulanine-glycine)3 - glutamic acid - glycine. Bottom: idealized folding of this protein polymer, where the glutamic acid sidechains (+) are on the surface of the folds.
7.3 Idealized truncated octahedron assembled from DNA. This view is down the four-fold axis of the squares. Each edge of the octahedron contains two double-helical turns of DNA.
7.4 An elastomeric stamp (top left) is made from an original master (bottom left). The stamp is dipped into the biological material (top right) and the pattern is transferred to the substrate (bottom right).
7.5 Mushroom-shaped clusters formed from self-assembly of rod-coil molecules; these clusters can undergo further packing to form sheets.
7.6 Novel combinations of DNA, metal ligands, DNA templating, and proteins are being investigated for molecular wires, inductors, and switches (photo courtesy of Shionoya and coworkers, Inst. for Molecular Science).

Published: September 1999; WTEC Hyper-Librarian