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Free keywords:
nanotubes; carbon nanotube; NEMS; MEMS; molecular beam epitaxy; roll curl; nanorings; nanorods; membrane
Abstract:
Strained semiconductor bilayers are released from their
substrate and formed into free-standing tubes, rods and rings
on semiconductor surfaces. We present nanotubes based on the
InGaAs/GaAs, SiGe/Si, and InGaP material system. The inner
diameters of our tubes vary from 15 to > 500 nm. We present
rolled-up nanotubes, which have performed up to 30 revolutions.
The wall thickness of the nanotubes depends on the number of
rotations. as a consequence , the inner to outer diameter ratio
can be tuned over a wide range, i.e from 1 to 0.125. In the
latter case the nanotubes become nanorods. Strained layers are
bent in two directions, vertical and horizantal. The result are
ultra-thin and ring-like vertical free-standing membranes. The
wide range of possible materials and structural properties make
these tubes and rings interesting candidates for fundamental
investigations as well as for applications (C) 2002 Elsevier
Science B.V. All rights reserved.
