Figure 2. Island shapes (AFM phase images) for different metal-species/Si-orientation combinations: (a) Au/Si(001), (b) Au/Si(111), (c) Sn/Si(110), and (d) Au/Si(110) .

1
Shape control of ordered semiconductor
nanostructures DMR-0349257 Oscar D. Dubón,
Jr. U.C. Berkeley
The organization of nanoscale elements into
higher order systems remains a fundamental
challenge in nanoscience and nanotechnology.
Dubón and co-workers have discovered a novel
growth process that combines rudimentary metal
patterning and natural self-assembly processes
for the realization of germanium nanostructure
arrays on silicon (Fig. 1).
Figure 1. (left) Optical diffraction from
Au-patterned Si covered with over 100,000 Ge
islands. (right) Representative atomic force
microscopy (AFM) zoom-in image of Ge islands that
have ordered into a 2D square lattice (height
scale100 nm). The color (red) in the left image
arises from the island spacing.
Island-shape control within the patterned region
is achieved by the choice of patterned metal
species and crystallographic orientation of the
Si surface (Fig. 2). These investigations
suggest an intimate relationship between Si-Ge
intermixing and island morphology.
The surface-diffusion-based dynamics of the
ordering process point to the possibility of
forming a variety of nanostructure arrays in this
and other semiconductor systems.
Figure 2. Island shapes (AFM phase images) for
different metal-species/Si-orientation
combinations (a) Au/Si(001), (b) Au/Si(111),
(c) Sn/Si(110), and (d) Au/Si(110) .
2
Shape control of ordered semiconductor
nanostructures DMR-0349257 Oscar D. Dubón,
Jr. U.C. Berkeley
Education, training, outreach

• Integrating research concepts in the
  classroomWhether in graduate school or in
  industry, new college graduates will tackle
  problems requiring innovative solutions. The
  successful engineer and future scientist must be
  able to gather information from a wide variety of
  sources, synthesize new concepts from this
  information and convey his/her findings to a
  technical community and even the public at
  large. In the capstone course taught by Dubón,
  engineering seniors perform advanced library
  research, carry out peer collaborations and
  reviews, analyze original data produced in
  Dubón's research labs, and write a technical
  paper. These activities cultivate important
  skills that will enable students to better meet
  challenges in science and technology.
• Training the future scientists through
  cutting-edge research experiencesA major
  objective of this project is to train future
  scientists and engineers, who will become leaders
  on the global stage. Both graduate and
  undergraduate students conduct original research
  and present their work at scientific conferences.
  In addition, students are encouraged to expand
  their scientific horizons through programs such
  as NSF's East Asian and Pacific Institutes
  (EAPSI) Program.
• Reaching audiences beyond the classroom and
  laboratoryKey to developing a strong, diverse
  workforce is to build an effective pipeline
  across education levels. To this end, Dubón has
  participated in the Summer Undergraduate Program
  in Engineering Research at Berkeley (SUPERB), a
  program designed to provide research
  opportunities in engineering to students who have
  been historically underrepresented. As a
  panelist, invited speaker, and SUPERB executive
  committee member, Dubón has sought to share his
  experiences and insights with program
  participants. In addition, Dubón served as a
  session co-organizer and co-chair (with Dr. J.
  Santiago-Aviles and Dr. L. Martinez-Miranda) for
  the 2004 National Meeting of the Society for the
  Advancement of Chicanos and Native Americans in
  Science. The session "Engineering Applied
  Physics, Materials Science, and Biophotonics" was
  sponsored in part by NSF.