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The Experimental Condensed Matter Physics Group at Virginia Tech is
carrying out research on a variety of unique materials including fullerenes,
semiconducting polymers, photorefractive polymers, crystalline and amorphous semiconductors,
nanocrystalline solids, sol-gel materials, and ceramic oxides.
The issues addressed include new phenomena in nonlinear optics, organic optoelectronics,
image processing, tribology, and spectroscopic effects of ultra-small crystallite size.
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Heflin's
research group focuses on organic self-assembled
optoelectronic nanostructures and devices. Areas of investigation
include ionic self-assembled multilayers for polar second
order nonlinear optics, nanoscale control of composition
in organic photovoltaics comprising semiconducting polymers
and fullerenes, biosensors based on self-assembled films
on optical fiber long period gratings, anti-reflection coatings
via nanoparticle self- assembly, and patterned self-assembly
for nanoscale electronic devices. This effort is part of the
Center for Self-Assembled Nano- structures and Devices
(CSAND).
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Prof. Heflin (right) discussing the results
of an experiment with his students.
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Student applying Indium as electrical
contacts to a sample in Prof. Heremans' Lab.
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Heremans'
laboratory studies the physics of controllably fabricated
semiconductor, metal and organic nanostructures, through their
electronic and magnetic properties. Areas of study include spin
electronics and spin-dependent, quantum-coherent electronic transport in
nano-patterned semiconductor heterostructures;
electronic transport in molecular systems; electronic transport in
organic semiconductor structures; and magnetic sensor geometries on
high-mobility semi- conductors.
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The lab utilizes in-house nanoscale
fabrication techniques such as electron beam and scanning probe
lithographies, and various patterning and deposition techniques.
Measurements occur at typically very low excitation levels, low
temperatures (0.3 K), and under magnetic fields (up to ∼10 T). Apart
from the fabrication equipment, the lab houses measurement cryostats,
characterization equipment (SEM, AFM, profilometer, optical
microscopes), and equipment for sensitive electronic measurements.
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Prof. Heremans (right) working in
his lab with Dr. Hong Chen (left).
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Student working with lasers in
Prof. Khodaparast's Lab.
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Indebetouw
investigates the properties
of phase-conjugate resonators: their spatio- temporal dynamics, and
their applications in image processing and optical computing.
He is investigating the potentials and limits of the methods of
digital and scanning holographic microscopy, as well as their
applications to structural (phase) and functional (fluorescence)
biological imaging.
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Khodaparast's
research activities are focused on understanding the quantum states
and charge/spin dynamics in low-dimensional systems.
She uses magneto-optical and time-resolved ultrafast spectroscopy to study materials
such as semiconductor hetero- structures, magnetic semiconductors, and quantum dots.
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Prof. Khodaparast (center)
working in her lab with her students.
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Student working on the superconducting
magnet in Prof. Khodaparast's Lab.
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These research activities will develop concepts for new devices as well as elucidate
fundamental physics.
The experimental facilities utilized include a femtosecond near-infrared laser,
a parametric optical amplifier, and cryogenic equipments.
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Ritter's
research focuses on layer-by-layer self-assembly of
anti-reflection coatings and on techniques for printing copies of
electronic- device templates that have been created by the self-assembly process.
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Prof. Ritter working on the electron-beam
evaporator with a student.
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Student preparing sample for nanosphere
lithography in Prof. Robinson's Lab.
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Robinson's
group combines high sensitivity optical and electrical measurement
techniques to investigate the physics of semiconducting and metallic
nanostructures.
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Projects include investigations of optically manipulated
single electron spins and spin currents in reduced-dimensional nanostructures
at low temperatures, and the use of localized plasmonic resonances on metallic
nano- structures to enhance non-linear effects such as second harmonic
generation, Raman scattering, and the electro-optic effect.
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Student working in Prof. Robinson's Lab.
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Students working on the Atomic Force
Microscope in Prof. Soghomonian's Lab.
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Soghomonian's group focuses on the synthesis, fabrication and
characterization of biological, organic, and hybrid organic/inorganic
nano- scale devices and assemblies.
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Areas of study include charge
transport measurements through variously modified DNA molecules to
elucidate the relationship of DNA structure to its charge transport
properties, charge transport measurements in organic and bioorganic
single crystal and thin film geometries to elucidate charge injection
characteristics in these systems, atomic force microscopy studies of
self-assembled patterns of biomolecules on various surfaces, and hydro-
and solvo-thermal synthesis of novel zeolitic materials with desired
functionalities.
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Student working in the clean room
of Prof. Soghomonian's Lab.
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Student operating the vacuum deposition
chamber in Prof. Heflin's Lab.
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Zallen
works on the optical properties of solids and on the
applications of condensed-matter concepts to cell-pattern
development during morphogenesis.
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Experimental facilities include Raman- scattering,
triboemission spectroscopy, infrared and visible-ultraviolet spectroscopy,
equipment for measuring magnetic and electrical properties, and
laser systems for experiments in physical and nonlinear optics.
Collaborations exist with groups in the Departments of
Chemistry,
Chemical Engineering,
Electrical & Computer Engineering, and
Materials Science and Engineering.
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Student operating the automatic dipping
machine in the Physics Dept. Clean Room.
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Research is supported by grants from the
NSF Division of Materials Research (DMR-0094055, DMR-0103034, DMR-0507866, DMR-0618235),
NSF Division of Electrical and Communications Systems (ECS-9907747, ECS-0524625),
NSF Advance Program (SBE-0244916),
Air Force Office of Scientific Research,
and the Jeffress Memorial Trust Fund.
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