|
Speaker:
Chandrasekhar Kothapalli
Advisor:
Dr. Mei Wei & Prof. Montgomery Shaw
Bio:
Graduated in 2000 with B.Tech in Chemical engineering from
Andhra University
,
India. Finished Masters in Chemical
Engineering from Mississippi State
University in 2002 and currently doing
Ph.D. at
University
of
Connecticut
specializing in Biomaterials.
Topic:
Influence of temperature and concentration on the sintering behavior and
mechanical properties of hydroxyapatite.
Abstract:
Human bone mineral contains calcium-deficient crystalline hydroxyapatite (HA)
embedded in collagen fibers. Research over the past two decades has focused on
preparing synthetic HA, which closely resembles bone apatite and exhibits
excellent osteoconductivity. This paper describes the synthesis of
nano-hydroxyapatite particles via a wet precipitation method. The concentration
of the reactants and the temperature of the reaction were varied. The length and
breadth of the HA particles were found to increase with the temperature, while
the aspect ratio increased with both the concentration and the temperature. The
average length of the particles was in the range 53-165 nm and the average
breadth in the range of 29-52 nm. A maximum strength of 57.4 MPa was observed
for the specimens 2.0-70 which also attained the highest density, 92%.
Speaker: Burc Misirlioglu
Advisor: S. Pamir Alpay
Bio: Burc Misirlioglu got his B.S. and M.S. degrees in
Metallurgical Engineering from
Istanbul Technical
University. He is currently enrolled as a
Ph.D. student at the University
of Connecticut
in the Department of Materials
Science&Engineering. His research is on the effects of defects such as
dislocations on the properties of ferroelectric thin films and is also
conducting research on PLD growth of ferroelectric thin films to study
structural characteristics of phase transformations in ferroelectric thin films.
Topic:
A Challenge Awaiting Nanoscale Device Engineering: Supression of
Ferroelectricity in Ultrathin Epitaxial Thin Films
Abstract:
Dislocations are the most common type of secondary defects and are unavoidably
present in all crystalline materials. They have been observed in ferroelectric
materials as in many other materials systems. Ferroelectrics have gained great
interest due to their special properties such as spontaneous polarization,
electric field dependent high dielectric constant and pyroresponse. When in
ferroelectric films, dislocations severely effect the physical properties of the
films designed for various applications confirmed by several experimental
studies. In this study, we supply experimental and theoretical evidence to
explain why they may have a significant impact on the degradation of the
electrical properties and change the phase transformation characteristics in
epitaxial ferroelectric thin films.
Speaker: Jason S Tresback
Advisor: Nitin Padture
Bio: Working
Jason Tresback received his B.S in Chemistry from the UniversityMassachusetts,
Amherst, in 2002. He also satisfied the requirements for a minor in Physics. His
undergraduate research areas include organic synthesis and nanotechnology.
He began the M.S in MS&E during the summer of 2003 and has been working on
the synthesis and characterization of multi-layered nanowires under Dr. Nitin
Padture’s guidance. He plans to begin the PhD at The Ohio State
University, Columbus, in fall 2005, upon successful completion of the M.S.
Topic:
Synthesis and Characterization Of Engineered Metal-Oxide-Metal nanowires
Abstract:
There has been growing interest in the “bottom up” approach to building
nanoelectronic devices, where nanoscale building blocks, such as nanowires
(metals, semiconductors, oxides), are fabricated in isolation and assembled into
nanocircuits. The “bottom up” approach offers several key advantages over
the conventional “top down” microelectronics approach, including higher
circuit densities and processing compatibility. Current nanoelectronics
technology uses nanowires that are assembled across photo-lithographically
deposited metal contact-pad electrodes to create devices. In this case, the
length of the nanowire spanning the electrodes defines the active region, which
is very difficult to control precisely. In order to address this critical issue,
we propose the concept of the engineered metal—oxide—metal (MOM) nanowire,
which is a metal nanowire (50 to 100 nm diameter; Au or Pt) with a small segment
(50-100 nm length) being replaced by a functional oxide. In other words, a MOM
nanowire has a functional oxide of precise dimensions with metal interconnects
integrated within the building block. The functional oxide can be a sensor,
ferroelectric, dielectric, semiconductor, or magnetic material. Thus, the MOM
nanowires have the potential to take the field of “bottom up”
nanoelectronics to the next level of sophistication and control. We have used
two different methods of electrochemical deposition within porous templates to
synthesize such MOM nanowires. Both methods are generic, and they can be used to
fabricate a wide variety of MOM nanowires. We have synthesized one example of a
MOM nanowire consisting of Au—SnO_2 —Au segments (gas sensor). Synthesis
methods, characterization results from the MOM nanowires, and the assembly of
the nanowires into functional nanodevices will be discussed.
Topics
as a PDF file
|
