Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-15T02:40:00.082Z Has data issue: false hasContentIssue false
  • English
  • Français

Ultrafine Metal Particles in Porous and Dense Silica Gels*

Published online by Cambridge University Press:  29 November 2013

Edward J.A. Pope  and
J.D. Mackenzie
Get access

Extract

The present trend of developing electronic devices with increasingly fine dimensions borders on a number of fundamental scientific questions about the very nature of how materials at ultrafine dimensions behave. This article addresses some of these questions. The fabrication of discrete metallic phases in porous and nonporous glassy matrices presents a number of exciting device possibilities. Methods of fabricating ultrafine metallic phases in silica via the sol-gel route are presented.

In attempting to fabricate materials with ultrafine physical dimensions for a wide variety of applications, several fundamental questions arise about the nature of materials behavior. For example, how many metal atoms are necessary to form a cluster exhibiting “metallic“ properties? Moreover, does the number of atoms necessary depend upon which metallic property is examined? This question has been partly addressed by D.C. Johnson and co-workers with regard to magnetism in osmium clusters. Their results show a threefold increase in magnetic susceptibility between clusters containing 3–10 osmium atoms.

Another important question, especially when considering device applications, is how the relative contributions of surface and bulk thermodynamics affect such properties as phase transformations. In addition, ultrafine phase dimensions interact with the fundamental unit lengths of a wide range of processes, including the wavelength of visible light, the mean free path lengths of conduction processes, the wavelengths of phonon vibrations, etc. How do these interactions affect optical, thermal, and electronic properties?

Fabrication of ultrafine metallic particles in porous and nonporous matrices may lead to many possible device applications including heterogeneous catalysts, nonlinear optic devices, highvoltage switching devices based on interparticle tunneling, and perhaps even new types of charge storage devices (capacitors).

Type
Technical Features
Information
MRS Bulletin , Volume 13 , Issue 3 , March 1988 , pp. 20 - 23
Copyright
Copyright © Materials Research Society 1988

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

*

This paper was presented at the symposium on Multicomponent Ultrafine Microstructures at an MRS Meeting.

References

1.Johnson, D., et al., Nature 314 (March 21, 1985) p. 231.CrossRefGoogle Scholar
2.Kadokura, K., “Phase Transformations of Submicron Particles in Porous Glasses,” PhD Dissertation, University of California, Los Angeles, 1983.Google Scholar
3.Nasu, H. and Mackenzie, J.D. (in press).Google Scholar
4. “Report on Artificially Structured Materials,” National Research Council (National Academy Press, Washington, DC, 1985).Google Scholar
5.Ganzenmüller, W., Glastech. Ber. 15 (1937) p. 346–353, 379–384.Google Scholar
6.Weyl, W.A., “Colored Glasses” (Society of Glass Technology, Sheffield, England, 1951).Google Scholar
7.Zsigmondy, Z., Z. Physikal. Chem. 56 (1906) p. 77.CrossRefGoogle Scholar
8.Bilisoly, J.P., U.S. Patent No. 2 496 265 (February 7, 1950).Google Scholar
9.Morgan, P.E.D., in Better Ceramics Through Chemistry II, edited by Brinker, C.J., Clark, D.E., and Ulrich, D.R. (Mater. Res. Soc. Symp. Proc. 73, Pittsburgh, PA, 1986) p. 751–763.Google Scholar
10.Roy, R.A. and Roy, R., Mat. Res. Bull. 19 (1984) p. 167.Google Scholar
11.Hoffman, D., Komarneni, S., and Roy, R., J. Mat. Sci. Lett. 3 (1984) p. 439.CrossRefGoogle Scholar
12.Pope, E.J.A. and Mackenzie, J.D., J. Non-Cryst. Solids 87 (1986) p. 185–198.CrossRefGoogle Scholar
13.Pope, E.J.A. and Mackenzie, J.D., Better Ceramics Through Chemistry II, edited by Brinker, C.J., Clark, D.E., and Ulrich, D.R. (Mater. Res. Soc. Symp. Proc. 73, Pittsburgh, PA, 1986) p. 809–814.Google Scholar
14.Pope, E.J.A. and Mackenzie, J.D., 21st University Conference on Ceramic Science, Pennsylvania State University, July 17-19, 1985 (Plenum, New York, 1986).Google Scholar