From: John Clark (jonkc@worldnet.att.net)
Date: Sat Sep 12 1998 - 23:11:09 MDT
PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 390 September 10, 1998 by Phillip F. Schewe and Ben
Stein
NANOTUBE NANOLITHOGRAPHY. Carbon nanotubes have
previously been used as tips in atomic force microscopes (AFM)
for producing images. But now for the first time nanotube tips have
been used as pencils for writing 10-nm-width structures on silicon
substrates. Ordinary graphite pencils write by wearing themselves
down, but this is not the case with nanotube pencils developed at
Stanford by Hongjie Dai (hdai@chem.stanford.edu, 650-725-4518)
and his colleagues. The robustness of the nanotube tips permits a
writing rate---0.5 mm/sec---five times faster than was possible with
older AFM tips. The way the nanotube writes is for an electric
field, issuing from the nanotube, to remove hydrogen atoms from
a layer of hydrogen atop a silicon base. The exposed silicon surface
oxidizes; thus the "writing" consists of narrow SiO2 tracks. The
Stanford results should help the development of nanofabrication,
since tip wear problems have been an obstacle to the use of probe
microscopes in lithography and data storage at the nm size scale.
(Dai, Franklin, and Han, Applied Physics Letters, 14 September
1998; figure at www.aip.org/physnews/graphics)
This archive was generated by hypermail 2.1.5 : Fri Nov 01 2002 - 14:49:34 MST