Professional Preparation
University of Chicago - 1967
University of Chicago - 1962
Massachusetts Institute of Technology - 1959
Research Areas
Research Interests
During my academic career, I have mentored 25 students to their Ph.D. (22 at UTD). My experimental work centers on the measurement of optical properties of solids with emphasis on modulation spectroscopy, Raman scattering and photoluminescence. Materials recently or currently studied include III-V compounds, both wide and narrow band gap semiconductors, elemental amorphous materials, nanomaterials, semiconducting silicides, thermoelectric materials and photonic crystals.
Projects:
1. Properties of metal silicides. These have importance as silicon based light emitting devices. An ion-implanted FeSi2 device, emitting light at 1.5 microns, was developed at the University of Surrey, England. It is exciting because a silicon based infrared emitter is economically desirable for long distance fiber optic communication. This work has been the trigger for a full exploration of the electronic and vibrational properties of semiconducting silicides including FeSi2, OsSi2 and Ru2Si3. We have studied these materials by Raman and photoreflectance spectroscopies.
2. Wide band gap semiconductors, particularly GaN and AlN. These are of interest for blue and ultraviolet LEDs and lasers. We have a vacuum ultraviolet modulated reflectivity spectrometer with which we have been studying these materials out to 10 eV.
3. Narrow gap semiconductors, particularly InGaSb alloys. Moving toward the other end of the spectrum we have developed an apparatus that is capable of measuring modulated reflectivity (photoreflectance or electroreflectance) signals in the mid infrared. At this point, we have demonstrated our ability to measure photoreflectance signals down to 0.5 eV.
4. We are developing photoreflectance as a contactless technique for studying defect and surface states in semiconductors. It is basically an optical deep-level-transient-spectroscopy (DLTS) technique and requires measurements of photoreflectance spectra as a function of modulation frequency and temperature.
5. In collaboration with the NanoTech Institute at UTD, we are investigating hydrogen storage properties of nanotubes.
Student Involvement-Present and Past.
In the context of local ties with the semiconductor industry, several of the UTD Ph.D. graduates from our group deserve particular mention. Dr. Gary Frazier is the manager of the Nanoelectronics group at Raytheon. Prior to assuming his managerial responsibilities, he was a TI Fellow. Dr. Joe Estrera is Chief Technology Officer and Director of Engineering for Northrop Grumman in Garland, Texas. Also, Dr. Tim Ostromek, Dr. Adriana Giordana and Dr. Loig Bourree are research scientists at Northrop Grumman. Dr. Glen Birdwell is a research scientist at MEMC in Sherman, Texas. Dr. Steve Collins is manager of research programs for the NanoTech Institute at UTD. Currently, Justin Schaefers is working on a collaborative Ph.D. project with Northrop Grumman.
Publications
Appointments
Northrop Grumman/Litton, Garland, Texas [2002–Present]
Northrop Grumman/Litton, Garland, Texas [2001–2018]
University of Surrey, Guildford, Surrey, England [1996–1997]
Litton/Varo, Garland, Texas [1993–2018]
Varo/IMO, Garland, Texas [1992–2018]
Varo/IMO, Garland, Texas [1991–2018]
The University of Texas at Dallas [1990–Present]
Naval Research Laboratory, Washington, D.C., [1990–2018]
Naval Research Laboratory, Washington, D.C., [1986–2018]
Varo, Inc., Garland, Texas [1984–2018]
Additional Information
Physics Community Activities
- Reviewer: Department of Physics at the University of Memphis, Memphis, Tennessee. Member of two-person outside review team to provide "instructional assessment" as required by the Tennessee Higher Education Commission. Review conducted on April 3-4, 1995.
- Chairman: Semiconductors: Nonlinear Optical Properties Session, American Physical Society Meeting, San Jose, California, March 1995.
- Member: Advisory Board for Consortium for Nanoscale Materials. (A regional center for solid state research under the sponsorship of the Oak Ridge Association of Universities with participation from universities including University of Maryland, John Hopkins, Pennsylvania State, Vanderbilt and others) 1992-1997.
- Member: Organizing Committee for 13th Annual Symposium on Electronic Materials, Processing and Characterization, June 6 & 7, 1994.
- Member: Organizing Committee for 12th Annual Symposium on Electronic Materials, Processing and Characterization, June 7 & 8, 1993.
- Chair: Solid State Devices Session, Joint Spring Meeting, Texas Sec. A.P.S., A.A.P.T. and S.P.S., Dallas, 4-5 April, 1986.
- Member: Local Arrangements Committee, First International Laser Conference, Dallas, Texas, 17-22 November 1985.
- Chair: Palladium and Palladium Alloys Session, Hydrogen in Metals International Symposium, Belfast, Northern Ireland, 26-29 March 1985.
- Chair: Hydrogen in Metals Session, American Physical Society Meeting, Dallas, Texas, March 1982.
- Member: Local Arrangements Committee, American Physical Society Meeting, Dallas, Texas March 1982.
Invited Talks/International Program Committees
- Member International Program Committee for the International Conference on Optical and Optoelectronic Properties of Materials and Applications (ICOOPMA) 2006, 15-23 July, 2006, Darwin, Australia
- Invited Speaker for International Workshop on Modulation Spectroscopy of Semiconductor Structures in Wroclaw, Poland July 1-3, 2004.
- Photoreflectance Applied to III-V Quantum Wells, Invited talk at the Physics Department of the University of Surrey, Guildford, Surrey, England, October 9, 1996.
- Porous Silicon, Invited Colloquium for the Physics Department of The University of Texas at Arlington, May 3, 1995.
- Determination of Hydrogen Concentration in Thin Films of Absorbing Materials, with M.W. Lee, presented at the NATO Advanced Study Institute on Amorphous Hydrides, Rhodes, Greece, 9-19 September 1985.
- Resistivity of Thin Films of the Palladium-Hydrogen System as a Function of Film Thickness with M.W. Lee, presented at the Hydrogen in Metals International Symposium, Queens University of Belfast, Northern Ireland, 26-29 March 1985.
Societies
- Sigma Xi
- American Physical Society