Effects of elastic field anisotropy on the heteroepitaxial growth of Ge quantum dots on vicinal Si surfaces
CFM Seminars
- Speaker
-
L. Persichetti, Dipartimento di Fisica, Università di Roma "Tor Vergata", Via della Ricerca Scientifica, 1-00133 Roma, Italy
- When
-
2012/11/19
13:00 - Place
- Auditorium of the Centro de Física de Materiales, Paseo Manuel de Lardizabal 5, Donostia-San Sebastián
- Add to calendar
- iCal
**_Effects of elastic field anisotropy on the heteroepitaxial growth of Ge
quantum dots on vicinal Si surfaces_** ** __****__**
_L. Persichetti 1 _*
1Dipartimento di Fisica, Università di Roma "Tor Vergata", Via della Ricerca
Scientifica, 1-00133 Roma, Italy
*Email: persichetti@roma2.infn.it
Engineering the growth of strained epitaxial films is a fascinating
perspective in modern nanoscale science. To this purpose, the challenge is to
control the strain-relief mechanisms which play a key role in the growth of
nanostructures. This can be done ‘‘artificially,’’ e.g., exploiting
patterning surface features or multilayered structures. A conceptually
different approach is the manipulation of heteroepitaxy through intrinsic
properties of the substrate. To make this prospect feasible, one has to
identify (1) distinct properties, which have impact on the growth process, and
(2) a simple and reliable way of tuning them. In strained-layer epitaxy, the
nature of the elastic field is a crucial parameter by definition. Since the
elastic forces in solid materials act at the nanometer range, these
interactions are particularly suited for bottom-up fabrication of
semiconductor quantum dots. This talk will discuss the possibility to control
the elastic environment of interacting Ge/Si islands by modulating the
substrate orientation with miscut angle [1].
First, we will show that a fine shaping of Ge islands is possible by changing
the miscut angle. This offers a direct way to easily alter the elastic-
interaction potential among islands, which strongly depends on the detailed
island’s shape [2-3].
Then, the breaking the isotropy of elastic interactions with miscut will be
discussed as a potential way to force the growth of Ge on vicinal Si surfaces
towards completely different pathways than on the flat substrate, as well as
to determine the local spatial ordering of nanostructures [4-6].
Finally, we will demonstrate experimentally the structural and energetic
changes induced by the epitaxial Ge deposition on the polar surface-energy
diagram of Si near the (001) face and their implications on the Stranski-
Krastanov growth nanofeatures [7].
[1] L. Persichetti, A. Capasso, A. Sgarlata, M. Fanfoni, N. Motta, and A.
Balzarotti, in _Self-Assembly of Nanostructures_ , S. Bellucci, Ed. (Springer
New York, New York, NY, 2012), vol. 12 of _Lecture Notes in Nanoscale Science
and Technology_ , chap. 4, pp. 201-263.
[2] L. Persichetti, A. Sgarlata, M. Fanfoni, and A. Balzarotti, Phys. Rev.
Lett. **104** , 036104 (2010).
[3] L. Persichetti, R. Menditto, A. Sgarlata, M. Fanfoni, and A. Balzarotti,
Appl. Phys. Lett. **99** , 161907 (2011).
[4] L. Persichetti, A. Sgarlata, M. Fanfoni, and A. Balzarotti, Phys. Rev.
Lett. **106** , 055503 (2011).
[5] L. Persichetti, A. Sgarlata, M. Fanfoni, and A. Balzarotti, Phys. Rev. B
**82** , 121309(R) (2010).
[6] L. Persichetti, A. Sgarlata, M. Fanfoni, and A. Balzarotti, Phys. Rev. B
**81** , 113409 (2010).
[7] L. Persichetti, A. Sgarlata, G. Mattoni, M. Fanfoni, A. Balzarotti, Phys.
Rev. B **85** , 195314 (2012).