These structures can be used as field emitters in plasma television screens.
Templates for fabricating sharply pointed microscopic peaks arranged in nearly regular planar arrays can be fabricated by a relatively inexpensive technique that has recently been demonstrated. Depending on the intended application, a semiconducting, insulating, or metallic film could be deposited on such a template by sputtering, thermal evaporation, pulsed laser deposition, or any other suitable conventional deposition technique. Pointed structures fabricated by use of these techniques may prove useful as photocathodes or field emitters in plasma television screens. Selected peaks could be removed from such structures and used individually as scanning tips in atomic force microscopy or mechanical surface profiling.
- Several small plates (e.g., microscope slides) made of a suitable (preferably transparent) rigid material such as glass, quartz, or sapphire;
- Two permanent magnets that produce a flux density of the order of 1 kG (0.1 T) with an acceptably low spatial variation over an area at least as large as that of the template to be formed; and
- A ferrofluid (consisting of Fe2O3 particles suspended in an oil-based solution that includes a surfactant).
The resulting structure is ready for use as a template for deposition. For example, Figure 2 shows selected views of such a template that has been coated with thermally evaporated silver.
This work was done by Diane E. Pugel of Goddard Space Flight Center.
This invention is owned by NASA, and a patent application has been filed. Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to the Patent Counsel, Goddard Space Flight Center, (301) 286-7351. Refer to GSC-14871-1.