Subsurface Damage in II-VI Semiconductors
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Date: 02-16-2006
Start Time:
10:00am
End Time: 11:00am
Speaker: Don A. Lucca
From:
Oklahoma State University
Location: 233 Mudd
Hosted by:
Center for Integrated Science
Abstract:
Ultraprecision finishing of the II-VI semiconductors, some of which
have applications in infrared optics (CdS, ZnSe) and as potential
substrates for short wavelength light emitters (ZnO, ZnSe), poses
particular challenges due to the unique chemical and structural
properties of these materials. Studies on their surface finishing have
demonstrated the achievement of superior surface finish and form
accuracy. However, subsurface lattice disorder introduced by the
process is known to persist and may pose severe limitations on both
surface performance and, for substrate applications, suitability for
subsequent epitaxial growth. Two investigations of the near surface
changes caused by surface preparation are presented. The first focuses
on the use of Rutherford backscattering in the channeling configuration
to study the nature, extent and distribution of subsurface damage in
finely finished bulk single crystals of CdS, ZnSe and ZnO. In the
second study, nanoindentation is used to investigate near surface
changes caused by surface preparation. The resulting mechanical
behavior of ZnO prepared by chemomechanical polishing, mechanical
polishing and chemical etching is presented. In particular, the effect
of surface condition on the critical load for the onset of plastic
deformation is examined.
Don A. Lucca is currently Regents Professor and Tom J. Cunningham Chair
in the School of Mechanical and Aerospace Engineering and a member of
the faculty of the School of International Studies at Oklahoma State
University. He also holds the position of Guest Scientist in the Center
for Integrated Nanotechnologies Group (MST-CINT) in the Materials
Science and Technology Division at Los Alamos National Laboratory. He
received a BS degree from Cornell, MSE from Princeton, and PhD from
Rensselaer Polytechnic Institute all in Mechanical Engineering. He is a
Fellow of the Society of Manufacturing Engineers, has received the
Alexander von Humboldt Research Award for Senior Scientists, and holds
an honorary doctorate from Universität Bremen. His current research is
directed towards developing basic understanding of the mechanics and
physics which govern microscale and nanoscale fabrication processes
used to create ultraprecision surfaces and thin films, and to
investigating the mechanical, chemical, electrical and photonic nature
of the surfaces which result.