2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009;
Pittsburgh, Pennsylvania
Session A12: Directed Organization of Nanostructured Films
8:00 AM–11:00 AM,
Monday, March 16, 2009
Room: 308
Sponsoring
Units:
DMP DCMP
Chair: Ray Phaneuf, University of Maryland
Abstract ID: BAPS.2009.MAR.A12.8
Abstract: A12.00008 : Hierarchical Assembly of Epitaxial Quantum Dot Nanostructures on Templated Substrates
9:48 AM–10:24 AM
Preview Abstract
Abstract
Author:
Robert Hull
(Rensselaer Polytechnic Institute)
Using the focused ion beam (FIB), we have modified the local
topography and
chemistry of Si(100) surfaces, and demonstrated control of the
geometry,
size, location and proximity of epitaxial Ge(Si) quantum dot (QD)
nanostructures which are nucleated on these templated surfaces.
We show how
QDs can be located with a precision $\sim $ 10 nm using local
Ga$^{+}$ FIB
doses $\sim $ 10$^{14}$ cm$^{-2}$, and how QD size and morphology
can be
modified by local surface chemistry. We further describe how
growth kinetics
can control formation of more complex nanostructures with
internal length
scales bridging the $\sim $ 10 nm dimensions necessary for
application to
potential nanoelectronic device architectures and dimensions that
are
accessible through external lithography. In particular, we
describe the self
assembly of ``quantum dot molecule'' (QDM) Ge$_{x}$Si$_{1-x}$
nanostructures
where a four-fold QD structures form around shallow strain
relieving pits.
Positional control of these QDMs using external lithographic
templating
allows formation of hierarchically assembled systems with length
scales
ranging from $\sim $ 10 nm in QD size and proximity, through the
$\sim $ 100
nm dimensions of the QDM, to the micro/macro-scopic dimensions
accessible
with external lithography. We also describe methods for
electronic and
magnetic functionalization of these nanostructures by separation
of ion
species from alloy liquid metal sources in a mass selecting FIB
column. This
allows generation of ion beams comprising electronically
non-invasive
species for nanoscale surface templating (e.g. Si, Ge),
electronic doping
(e.g. As, B), or spin doping (e.g. Mn). Application of such
structures to
potential novel nanoelectronic device structures will be discussed.
This work is done in collaboration with J. Floro, J. Graham, M.
Gherasimova, J. Thorp (UVa), F. Ross (IBM), A. Portavoce (CNRS),
M. Kammler (U. Duisburg) and J. Gray (U. Pittsburgh).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.MAR.A12.8