75th Annual Meeting of the Southeastern Section of APS
Volume 53, Number 13
Thursday–Saturday, October 30–November 1 2008;
Raleigh, North Carolina
Session KB: Forefront Materials Physics III
3:45 PM–5:45 PM,
Friday, October 31, 2008
Holiday Inn Brownstone
Room: Washington
Chair: David Aspnes, North Carolina State University
Abstract ID: BAPS.2008.SES.KB.3
Abstract: KB.00003 : A surface-driven approach to the synthesis of basic building blocks for the design of complex Si-Ge-Mn nanostructures
4:45 PM–5:15 PM
Preview Abstract
Abstract
Author:
Petra Reinke
(University of Virginia)
The combination of Silicon and Germanium with Manganese is highly
desirable for the development of novel spintronics devices. We
will describe a surface-driven approach to the tailored synthesis
of basic building blocks for the design of complex Si-Ge-Mn
nanostructures. The goals are to incorporate Mn as delta-doped
layers in a Si matrix, and to magnetically dope Ge-quantum dots.
These processes are studied with STM and photoelectron spectroscopy.
The Si(100)(2x1) surface functions as a template and Mn-nanowires
are formed which run perpendicular to the Si-dimer rows. The
bonding sites of the Mn-adatoms, the wire length and spatial
distribution are interpreted within the framework of recent
theoretical predictions. The bonding of Mn-adatoms changes with
temperature: at 500 K the adatoms move into sub-surface sites,
higher temperatures initiate silicide formation, which is
controlled by the Si- surface atom mobility.
In a next step we deposited a Ge-overlayer on the Mn-wires, and
used voltage dependent STM analysis to separate the Ge and Mn
contributions. In the low-adatom-mobility regime the Mn-wires are
preserved. The low temperature growth therefore offers a pathway
to create buried nanostructures in controlled manner.
The formation of Mn-doped Ge-quantum dots is approached by the
deposition of Mn on the Ge-QDs at 273 K. On both surfaces, the
Ge(100) wetting layer and the Ge (105) facet of the QDs, the Mn
adatoms form nanoclusters. On the Ge(105) facet the flat clusters
are aligned with respect to the reconstruction, and the wetting
layer surface is considerably roughenend. Annealing of the
surface structures to initiate a diffusion of Mn into the Ge-QD
bulk is investigated as a means to achieve local doping. However,
the annealing process leads to a highly complex response which is
extremely sensitive to temperature. While these processes are by
no means currently understood, we will offer a first qualitative
interpretation of the observed reactions.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.SES.KB.3