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This Raman Page is Under Construction!
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Raman Laboratory:
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Dr. Roughani - the director of the Raman
Lab.
Raman spectroscopy laboratory at Kettering
University, was established in 1996. The laboratory equipment were
obtained by Professor Roughani from the the US Army Research Laboratory
and through the "Educational Partnership" program.
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Raman spectroscopy laboratory, is part
of the Applied Physics program of Kettering University. It consist
of an SPEX-1403 double monochromator, an argon-ion laser source,
a PMT, a CCD camera, and a Raman Microprobe with spatial resolution
of one micron.
Professor BahRAM
RoughANi, in the Applied Physics
Raman Laboratory >>>>>>
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Raman Spectroscopy Laboratory (Room 1-905 AB):
The on-campus Raman
facility consist of a double monochromator, with holographic gratings,
a Raman microprobe with camera attachments, a CCD camera and a PMT photon
counting system all assembled on a vibration isolation optical table.
This facility is available for faculty and student research, as well
and research and consulting for scientific and technological applications.
The Raman Microprobe with
spatial resolution of one micrometer can be used for high resolution
spectroscopy of electronic materials, such as Si, SiC, GaAs/AlAs superlattices,
quantum wells, and high temperature superconductors. The excitation
source of this Raman scattering system is an argon-ion laser. A Spex-1403
double monochromator with holographic gratings of 1800 lines/mm is used
to disperse the scattered light. A Hamamatsu photomultiplier tube is
being used for photon counting. A CCD camera is also available for data
collection.
Plan for expanding the optical
spectroscopy at Kettering university include the completion of a photoluminescence
(PL) system. This PL system will complement the existing Raman facility,
and will be completed by professor Uma Ramabadran and professor Bahram
Roughani.
NOTE: For technical information regarding the Raman
Spectrometer please refer to the Jobi Yvon Ltd Web page.
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"The
purpose of model is not to fit the data, but to sharpen the questions"
(Samuel Karlin)
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Raman
Spectroscopy
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Raman
Spectroscopy
Raman
Spectroscopy is an inelastic scattering of light due to light-matter interaction.
It involves an inelastic process during which the energy of the incident
laser will be shifted. The measured shift in photon energy (measured in
unit of 1/cm) is the same as the energy of the phonon created or annihilated
in this process. In an Stocks process, phonons are being created, thus
the scattered photons have less energy. In the Anti- Stocks process, phonons
are being annihilated, thus the scattered photons gain energy. The coupling
of phonons with other excitations will allow to gain insight into various
electrical or magnetic excitations as well. Raman
scattering (RS) is a nondestructive, contact-less and powerful optical
spectroscopy technique for materials characterization, including the electronic
materials. It an be used for evaluating
- crystal
quality and crystal orientation
- composition
of alloy semiconductors
- carrier concentration
- scattering
time
- structural
and compositional disorder
- ion-damaged
- laser annealing
effect
- studying
the nature of oxides on compound semiconductors
- potential
fluctuations in alloy semiconductors
- studying
superlattice properties and interfaces
- determination
of strains
- etc.
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Research
Projects
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Research
Projects
- Spectroscopic analysis of
Carbon nano-structures that has been developed in our laboratory through
a solid reaction processing thecnique. This work that so far has included
five undergraduate Applied Physics students involves Raman scattering
measurements as well as SEM and XPS studies.
- Raman scattering studies
of Sic samples. Our samples have gone under various treatments including
chem-mechanical polishing (CMP), rapid thermal annealing (RTA) and high
temperature furnace annealing. Results of our Raman spectroscopy analysis
are being compared with our surface analysis of XPS (a.k.a. ESCA) done
on the same samples. This research project is a collaboration with the
Wright Patterson AFB in Dayton, Ohio.
- Depth profiling analysis
of electronic materials based on a theoretical model that we have developed
for such studies is underway. The results will be submitted for publications
shortly.
- Raman spectroscopy investigations
of GaAs/Alas superlattice structures. Raman spectroscopy analysis of
these superlattice structures are aiming at surface roughness analysis
of multilayered artificial structures. The interface roughness or structures
could have adverse effect on the electronic of optical characteristics
of superlattice based devices. This research project is a collaboration
with NIST, at Gaithersburg, Maryland.
- Raman scattering investigation
of polarization dependence of Raman intensity variation in Si wafers.
The crystal symmetry and the polarization direction of the incident
and the scattered lights are being analyzed as an effective tool for
crystal quality analysis. Our particular approach could be an effective
tool for introducing students to Raman spectroscopy, thus a version
of our results will appear in the Am. J. Phys.
- Contact-less temperature
measurement of semiconductor devices, and thermal mapping of high power
devices. Raman scattering can be used as a nondestructive technique
for local measurement of semiconductors. The intensity ratio of Stocks
and anti-Stokes peaks and the phonon peak softening could both provide
useful information on the local heating effects. These measurement could
be related to the defects in semiconductors that may lead to local heating
effects.
Kirk Anderson (Above), an undergraduate
Applied Physics student, working with the Raman Microprobe. Kirk and Jared
Parez designed a low cost thermal stage (shown below), as part of the
work for measuring the local temperature of Sic wafers.
The low cost thermal stage
(above), designed by Applied Physics students, Kirk Anderson, and Jared
Parez, to examine the accuracy of Raman microprobe in measuring the local
temperatures of semiconductor wafers and devices. This simple thermal
stage is built using a soldering iron and ceramic blocks for thermal insulation.
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"One
should never believe any experiment until it has been confirmed by theory"
Sir
Arthur Eddington
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Other
Research Facilities; XPS (a.k.a.. ESCA), Photoluminescence
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- X-ray Photoemission Spectroscopy
(XPS) a.k.a. Electronic Spectroscopy for Chemical Analysis (ESCA): This
laboratory facility was established through an NSF ILI project, in collaboration
with three faculty from Environmental Chemistry and one faculty from
Applied Physics discipline.
- Photoluminescence Spectroscopy:
This laboratory facility is being developed in collaboration with professor
Uma Ramabadran. The intend is to enhance the optical and advanced spectroscopy
facilities, which could enhance the Materials Science portion of the
Applied Physics degree program.
- Scanning Tunneling Microscopy
(STM) & Atomic Force Microscopy (AFM): These two scanning probe
microscopy techniques are part of a pending NSF CCLI grant proposal.
Development of an STM/AFM facility will enhance advanced undergraduate
laboratory facilities, while it will complement XPS, Raman and photoluminescence
spectroscopy capabilities.
- Other available laboratory
facilities within our department that could be combined with our existing
laboratory capabilities include, scanning electron microscopy (SEM),
and new environmental SEM (ESEM), FTIR.
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Raman
Links
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Last revised: November
17, 2001
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