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Nano Research & Applications
ISSN: 2471-9838
Volume 4
December 10-12, 2018
Rome, Italy
Advanced Materials 2018
Nano Engineering 2018
Page 32
JOINT EVENT
22
nd
International Conference on
Advanced Materials
and Simulation
&
22
nd
Edition of International Conference on
Nano Engineering &
Technology
Monolithic integration of Si based microelectronics and
optoelectronics is expected to be the viable solution to overcome
the performance of bottleneck for semiconductor microchips in
termsofpowerconsumption,speedandbandwidth.GeSiquantum
nanostructures (QNs) have been of great interest for their potential
in both microelectronic and optoelectronic device applications,
considering their unique properties and the compatibility with
the sophisticated Si technology. However, the poor quantum
efficiency of the Ge/Si system associated with the indirect band
structure hampers their applications in the optoelectronic devices.
It is found that the quantum confinement effect and the partial
relaxation of the lawof momentumconservation can considerably
increase the quantum efficiency of the Ge Si nanostructures.
Further improvement can be realized by embedding Ge Si QNs
into some micro cavities since the light-matter interaction in the
cavity can be dramatically enhanced. It is a critical issue to realize
the spatial matching, as well as the spectra matching, between
the Ge Si QNs and the cavity. In this talk, controlled Ge Si QNs in
Si microcavities (micropillars and microdisks) are systematically
studied. The periodic Si micropillars andmicrodisks are fabricated
by nano sphere lithography. Controlled Ge Si coaxial quantum
wells (CQWs) on periodic Si (001) micropillars in a large area is
realized. By tailoring the growth conditions and the diameters
of the pillars (or the microdisks), different configurations of
Ge Si QNs, including quantum dots (QDs) ‘necklace’, quantum
rings (QRs), quantum dot molecules (QDMs) and single QD are
realized on the top edge of the micropillars, as shown in Fig. 1.
By reducing the Si pillar into small dot, four self-assembled Ge Si
QDs can be induced at the base edges of the Si dot, resulting in
the Ge-Si compound QD molecules. Particularly, the Ge Si QNs
can be readily modulated by a two-step growth procedure. Such
an engineering of Ge Si QNs is explained in terms of the surface
chemical potential and the anisotropic surface diffusion of
adatoms around the patterned Si microstructures during growth.
Our results disclose the critical effect of the surface curvature on
the diffusion and the aggregation of Ge adatoms, which further
clarify the unique features and the inherent mechanism of self-
assembled QDs on patterned substrates. More interestingly, by
designing the diameter and the period of the Si microcavities
(pillars or disks), the strong coupling between the spontaneous
emission of Ge Si QNs and the cavity modes, as well as the effect
of the photonic crystal bandgap, will remarkably improve the
optoelectronic properties of the Ge Si QNs. Accordingly, the Ge Si
QNs embedded in the Si microcavities will have promising futures
in the applications of innovative optoelectronic devices.
Biography
Dr. Zhenyang Zhong is a Professor in the Physics Department at Fudan Uni-
versity, China. He has completed his BS at Peking University in 1995 and PhD
degree in the Institute of Physics at Chinese Academy of Science, Beijing, Chi-
na in 2001. He has worked in Institute for Semiconductor Physics at Univer-
sity Linz, Austria from April 2001 to December 2003 and from May 2005 to
December 2005 and worked in Max Planck Institute for Solid State Research,
Stuttgart, Germany, as a Postdoctoral Research Fellow fromApril 2004 to April
2005. Since 2006, he is working in the Physics Department at Fudan Univer-
sity. His research interest focuses on the controlled formation of varieties of
nanostructures on Si substrates, and the exploration of the unique properties
and the applications of those nanostructures. He has authored or coauthored
71 journal articles and 2 book chapters.
zhenyangz@fudan.edu.cnControlled self-assembly of
Ge Si nanostructures and its
perspective in Si micro cavities
Zhenyang Zhong
Fudan University, People’s Republic of China
Zhenyang Zhong, Nano Res Appl 2018, Volume 4
DOI: 10.21767/2471-9838-C7-026