(Press-News.org) WASHINGTON, D.C., (Oct. 20, 2010) -- Just as landscape photographs shot in low-angle light dramatically accentuate subtle swales and mounds, depositing metal vapors at glancing angles turns a rough surface into amazing nanostructures with a vast range of potential properties.
For decades, vapor deposition has been a standard technique for creating modern microelectronic circuits. But nearly all of industry's efforts have been devoted to making structures as flat and smooth as possible. Rather than placing metal sources in the high-noon position used to make featureless structures, Daniel Gall of Rensselaer Polytechnic Institute is one of several dozen research leaders who place them at very narrow angles akin to sunrise or sunset illumination. Metal atoms then hit primarily any high spots on the target surface. Continued deposition creates a forest of nanorods, rather than flat films, since each growing rod shadows a volume behind it. Starting with a patterned substrate yields a regular array of nanoscale columns, like skyscrapers in downtown Manhattan.
Gall describes his research today at the AVS 57th International Symposium & Exhibition, which takes place this week at the Albuquerque Convention Center in New Mexico.
In his talk, Gall reveals a new theory that predicts how the deposition temperature and diffusion affects the diameters of the nanorods.
"Atoms moving by surface diffusion typically smooth the surface," Gall says. "Atomic shadowing causes the opposite effects, making the surface rough. Glancing-angle deposition extends shadowing effects to higher temperatures, which lead to larger-diameter nanorods."
He also illustrates his presentation with images of a variety of nanostructures created in his lab, including curiously shaped half-moons made when he started with a pattern of self-assembled spheres.
Future applications for nanorod structures such as Gall's include nanosensors, optical elements, fuel-cell cathodes and electrical contacts for buffering thermal expansion.
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The presentation, "Nanorods by Extreme Shadowing: New Pictures and New Physics" is at 2:40 p.m. on Wednesday, October 20, 2010.
ABSTRACT: http://www.avssymposium.org/Open/SearchPapers.aspx?PaperNumber=SE+TF-WeA-3
MORE INFORMATION FOR JOURNALISTS
The AVS 57th International Symposium and Exhibition is being held October 17-22, 2010, at the Albuquerque Convention Center, in Albuquerque, New Mexico. The meeting includes more than 1,200 talks and posters presented in more than 130 technical sessions. All meeting information, including directions to the Convention Center, can be found at:
http://www2.avs.org/symposium/
REGISTRATION -- Staff reporters and professional freelance journalists working on assignment are invited to attend the conference free of charge. Journalist registration instructions can be found at:
http://www2.avs.org/symposium/AVS57/pdfs/pressinvite.pdf
PRESS ROOM
The AVS press room will be located in East Lobby of the Albuquerque Convention Center. Press room hours are Monday-Thursday, 8:00 a.m. to 5:00 p.m. The phone number there is 408-205-0595. Press Kits containing company product announcements and other news will be available on CD-ROM in the press room. Also access the online press room at: http://www2.avs.org/symposium/AVS57/pages/press57.html
USEFUL LINKS
Complete Program: http://www2.avs.org/symposium/AVS57/pages/tech_program.html
Searchable abstracts: http://www.avssymposium.org/Open/SearchPapers.aspx
Topical Conferences: http://www2.avs.org/symposium/AVS57/pages/tech_topconf.html#EN
Meeting Home Page: http://www2.avs.org/symposium/
PLENARY SESSION
The plenary talk, "Carbon Nanotubes and Single Sheet Graphene," which will be at noon on Monday, October 18, 2010 in Ballroom B of the Albuquerque Convention Center. See: http://www2.avs.org/symposium/AVS57/pages/sessions_lecturer.html
SPECIAL TUTORIALS
AVS promotes communication, dissemination of knowledge, recommended practices, research, and education in a broad range of technologically relevant topics. One way that it does this is by offering special tutorials in areas such as:
- Graphene Tutorial (Sunday, October 17, 2010, 1:00-5:00 p.m.)
- Tutorial on Nanoparticle Characterization and Toxicity: Significant Challenges and Critical Needs (Sunday, October 17, 2010, 1:00-5:00 p.m.)
To access the complete descriptions of these special tutorials, see:
http://www2.avs.org/symposium/AVS57/pages/special_tutorials.html
ABOUT AVS
As a professional membership organization, AVS fosters networking within the materials, processing, and interfaces community at various local, national or international meetings and exhibits throughout the year. AVS publishes four journals, honors and recognizes members through its prestigious awards program, offers training and other technical resources, as well as career services.
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