Projects

REU Research Projects and Mentors

Jerry Clark, WSU, atomic/plasma physics and optical spectroscopy of solids

1. Photoreflectance:  Measurement and analysis of Photoreflectance spectra for high bandgap semiconductor materials.  We are currently looking at nanostructures of ZnO and layers of GaN doped with carbon.  This would entail sample setup and data collection, software design or redesign of data collection programs (Labview), and design of programs to aid in the spectral analysis (various software possible).

2. Electroreflectance:  Design of a experimental system to acquire electroreflectance spectra from high bandgap semiconductors.  This would be a hardware design to construct the sample stage to modulate the sample with an external applied field.  This is like creating a transparent capacitor around the semiconductor sample.  The design and construction of the drive electronics and light detection system will be required.  Spectra acquired will be compared to that obtained by Photoreflectance. (hardware and solfware design)

3. Nonequilbrium Plasma Modeling:  An interesting problem is the influence of a shock wave on the ionization conditions in a gas discharge plasma.  A possible mechanism to attack this problem is to solve the time dependent Boltzmann transport equations with a variable pressure or pressure gradient.  This would entail the modification of Boltzmann Transport Codes or Monte Carlo codes which calculate the ionization rate and compare to experimental data.  These codes are written in Fortran. (software design)

Gary Farlow, WSU, Radiation damage studies of GaN and ZnO

The accelerator labs at Wright State University are presently engaged in a series of radiation damage studies of GaN and ZnO.  This material is both a wide-bandgap semiconductor and one that shows considerable resistance to radiation damage.  As part of this effort a variety of layers of GaN and ZnO are being irradiated with electrons having energies up to 2 MeV and at current densities of up to 3.3 microamps/cm².   There are simple models of radiation damage based on linear tacks and average energy deposition scaled by the calculated displacement energies.   These however do not seem to be adequate to model nor analyze the processes in GaN and ZnO in that they give damage rates in excess of 10 times what is observed (~20 /cm versus  1/cm).   

It is proposed to acquire the Tiger Codes from the computational archives at Oak Ridge National Laboratory.   These have the ability to input adjustable collision cross-sections, displacement energies and collision mechanisms.   Additionally the output of these codes can be input to the TRIM ion transport code to investigate any cascading and dynamic annealing effects.

The Tiger codes would have to be installed, tested and run under known conditions.  Then applied to the sample types and irradiation conditions we use in the accelerator laboratory.  

A computer savvy student, capable or independent work is needed to accomplish this purpose.  Familiarity with Fortran, Unix or Linux, as well as the standard Windows interface is desired.

Jane Fox, WSU, Atmospheric physics

Brent Foy, WSU, Bioinformatics

Gregory Kozlowski, WSU, superconductivity, nanophysics and materials science

Doug Petkie, WSU, Molecular spectroscopy, chemical physics, remote and in-situ sensing

Students can be involved in a wide range of experimental and/or computational activities relating to vibrational-rotational spectroscopy of small fundamental molecules in the millimeter wave region of the electromagnetic spectrum.  Molecules of interest are found in the upper atmosphere and relate to the ozone chemistry of the stratosphere, found in interstellar clouds in space, and found in exhaled human breath that relate to stresses caused by disease.  Experimental aspects include designing and constructing spectroscopic systems and absorption cells for new experiments and developing data acquisition techniques and software.  Computational and theoretical aspects relate to analyzing laboratory spectra of a specific molecule to determine its fundamental molecular properties and comparing these results with quantum chemistry calculations.  The spectroscopic results are also used to simulate infrared spectra recorded in the laboratory and by balloon observations made in the upper atmosphere.  See my homepage for more details: http://www.wright.edu/~doug.petkie/research.htm

Tom Skinner, WSU, magnetic resonance spectroscopy, optimal control theory

Glen Perram, AFIT, chemical physics, spectroscopy, lasers, remote sensing

Specific project descriptions:

1. Gas Phase Optical Diagnostics for the Manufacture of High Temperature Superconducting Wires

2. Remote Sensing of Bomb Detonations

Also visit: http://en.afit.edu/enp/Faculty/perram.html

Won Roh, AFIT, Lasers, optics, spectroscopy, image processing, phase conjugation, and nonlinear optics

Professor Roh’s group’s research activities at AFIT are clustered around nonlinear optics of optical fibers. Nonlinear optical processes form the basis for techniques for developing useful devices for optical systems, especially laser systems. The nonlinear processes we exploit are stimulated Brillouin scattering and stimulated Raman scattering. Optical fibers constitute an excellent nonlinear medium in this regard. When properly initiated in a multi-mode optical fiber, both of these processes produce a laser like beam that possesses a unique set of very interesting and useful properties. These properties include: beam cleanup which produces a beam with better propagation characteristics, beam combining which makes it possible to combine many beams to produce a single more powerful beam, phase conjugation which makes it possible to restore a distorted beam back to its original undistorted condition, and wavelength shifting which permits creation of a laser-like device that produces a coherent radiation at a new wavelength. At this time there are a number of experiments that are in progress or in planning stages. For example, an experiment to demonstrate phasing of beams from a multi-channel master oscillator/power amplifier (MC-MOPA) system using a fiber phase conjugate mirror. The phase conjugate mirror to be used is an amplifying multi-mode fiber that generates stimulated Brillouin scattering whose power is greater than the input pump. Within this project there are some building block experiments to be performed as well. The prospective WSU REU student will be assigned to one of these experiments. It would be desirable for the WSU REU student to have a background in optics, fiber, and/or lasers.

http://en.afit.edu/enp/Faculty/roh.html

Steve Adams, Plasma Physics Branch of AFRL, plasma physics laser diagnostics of gas discharges

Our research within the Plasma Physics Branch of the Propulsion Directorate at the Air Force Research Laboratory at Wright-Patterson AFB involves laser diagnostics of excited nitrogen.  Laser spectroscopy is used to investigate the ionization processes in low to near atmospheric pressure discharges in air and nitrogen. Understanding these ion processes are key to developing aerospace technologies such as plasma supersonic drag reduction that rely on maintaining a partially ionized gaseous state in flowing air.  Thus, accurate measurements of ion production and recombination phenomena in nitrogen and air are critical for pursuing these technologies.  Of particular interest within our group are pulsed laser diagnostics involving multi-photon absorption.  Laser induced fluorescence (LIF) as well as resonantly-enhanced multi-photon ionization (REMPI) techniques are used to probe electronically excited and ionized products of discharges in atmospheric N₂.   In addition, computer analysis of the resulting data includes application of kinetic theory to model the reactions and evolution of the reacting species.  Students are not expected to have a background in this specific area of research, but are expected to be willing to learn and work toward making contributions to the laboratory experiment or the data analysis.

 

Mike Durstock, AFRL/MLPJ

photovoltaics, fuel cells, high energy density dielectrics, polymer FET's, as well as chemical synthesis and processing of materials for these applications.

John Ferguson, Polymer Branch of AFRL, materials science of organic and polymeric materials

The Polymer Branch of the Air Force Research Laboratory, Materials & Manufacturing Directorate, Non-Metallic Materials Division (AFRL/MLBP) will participate in the program as a collaborative partner, providing a research projects for several undergraduate physics students.

Capabilities relevant to physics research include DC and AC characterization of electrical (charge transport) and dielectric properties, measuring time of flight charge carrier mobility, spectroscopy of mid-gap quasi-particle quantum states, electroluminescent and optical radiometry measurements, determination of photoconductive and photovoltaic quantum efficiency, intensity efficiency, power generation efficiency under laboratory standard simulated solar spectral light. Investigation of transport mechanisms is accomplished by measurement of these properties under temperature conditions between 4 Kelvin and 300 Kelvin.

Several of these scientific investigations are especially amenable for undergraduate students.  The direct measurement charge carrier mobility involves simple concepts from introductory physics involving distance, velocity and speed.  The conductivity and dielectric function also are basic to introductory physics.  Temperature activation of charge carrier transport connects well with concepts covered in most Modern Physics curriculum.  Spectroscopy of mid-gap quasiparticle quantum states gives students a hands on experience with the abstract quantum theory taught in Modern Physics as well as upper level undergraduate courses such as Solid State Physics and Quantum Mechanics.

The Polymer Branch, Materials and Manufacturing Directorate, Air Force Research Laboratory is a multi-disciplinary environment for scientific investigation of new organic and polymeric materials for Air Force enabling technologies.  The activities include chemical synthesis of new materials, development of new processing techniques and basic physical science investigations of new materials and devices.  Government research staff includes 4 synthetic chemists, 3 computational chemists, 5 materials engineers and 1 physicist.

Dave Look, WSU/AFRL, Properties of semiconductors (ZnO).