Joseph H. Simmons, Department Head and Professor

Ph. D. Catholic University of America (1969, Physics)
The University of Arizona
Materials Science and Engineering
1235 E. North Campus Drive
Tucson, AZ 85721-0012
e-mail: simmons@aml.arizona.edu

Teaching Interests:

• Atomic Bonding and Structure of Materials (MSE 260, 360)
• Introduction to Materials Science (MSE 222)
• Mathematical Methods for the Physical Sciences
• Physics and Chemistry of Ceramic Materials (MSE 524)
• Optical Properties of Materials (MSE 534)
• Structure and Properties of Glass (MSE 571)

Current Research Interests:

• Quantum-size effects in the optical properties of semiconductor clusters:
  Studies involve measurement and theoretical analysis of steady-state and time-resolved (femtosecond) photoluminescence and absorption behavior of quantum-size (12-400Å) semiconductor clusters in glass (CdTe, Si, Ge, GaAS, ZnSe, etc. in SiO₂ and ITO).



• Optical properties and carrier dynamics in wide-gap semiconductors:
  Research is conducted to identify and analyze the source and behavior of optical defects in wide-gap semiconductors, and to study the photoexcited carrier and exciton dynamics in undoped and heavily doped heterostructures using femtosecond lasers.



• Photosensitivity in glass films: This program involves collaborative research with Sandia National Laboratory to develop new materials with photosensitive characteristics for applications to Bragg gratings, optical and holographic memories and digital optics. Materials are formed that exhibit structural defect that can be optically modified and controlled by dopant selection.



• Non-linear optical behavior of materials and glasses:
  
  Theoretical and experimental studies of optical nonlinear processes in semi-conductors and glasses, are conducted to develop optimized materials for waveguide coupling applications i noptical communications. The program includes collaborations with Sandia National Lab and Lucent Labs in the development of rare-earth-doped thin films for lasers and optical amplifiers.



• Optical spectroscopy of materials at the nano-scale level:
  The research is centered about a spectroscopy facility in the MSE Dept. which consists of Raman, visible, infrated, flourescence and photoluminscence spectrometers linked to a Near-Field Optical Microscope (NSOM) using CW and femtosecond-pulsed lasers. Measurements are made with a spatial resolution of 0.1 microns that can be reduced to a few hundred angstroms.



• Molecular Dynamics simulations:
  
  1. optical properties of glasses and crystals in the presence of interfaces and surfaces:
     Simulations of the effect of structure and interfaces or surfaces on the crystal field splitting of doped rare earth ions are conducted to determine the associated optical transitions.
  2. multi-scale simulations of brittle fracture in glass and crystals:
     A Multi-investigator team studies the atomistic dynamics of solids under the application of strain to failure and in the presence of a reactive atmosphere. The research combines quantum mechanical modeling with classical ensemble dynamics in order to analyze the behavior of embedded clusters in a matrix and to investigate the propagation of cracks with and without environmental and thermal effects.
• Non-linear viscous flow and rheological behavior of molten glasses:
  Measurements of viscosity at low and high strain rates are conducted to determine the relationship between structural changes, structural relaxation and inherent strength of sheared liquids.

PUBLICATIONS (condensed version)

1. "Processing of Fine-Diameter, Continuous Mullite Fibers," S. Al-Assafi, T. Cruse, J. H. Simmons, A. B. Brennan and M. D. Sacks, Ceramic Transactions, Amer. Ceram. Soc., Columbus, OH, May 1994.
2. "Photosensitivity in Germano-Silicate Sol-Gel Thin Films," K. D. Simmons, G. I. Stegeman, B. G. Potter and J. H. Simmons, J. Non-Crystalline Solids 179, 254-259 (1994).
3. "GeO2 - SiO2 Thin Films for Planar Waveguide Applications," D. G. Chen, B. G. Potter and J. H. Simmons, J. Non-Crystalline Solids 178, 135-147 (1994).
4. "Graded-Index AR Coatings for Large Angles of Inclination," J. H. Simmons, S. J. Pagano, L. K. Downie, B. G. Potter, C. J. Simmons, E. N. Boulos and M. F. Best, J. Non-Crystalline Solids 178, 166-175 (1994).
5. "Increased Precision in Strain Measurement of Diamond by MicroRaman Spectroscopy," W. B. Alexander, P. H. Holloway, J. H. Simmons and R. Ochoa, J. Vac. Sci. Technol. A12, 2943-5 (1994).
6. "Band Bleaching and Growth Dynamics in 45% GeO2-SiO2 Films," K. D. Simmons and J. H. Simmons, Appl. Phys. Lett. 66, 2104-06 (1995).
7. "Observation of Exciton and Biexciton Processes in CdxZn1-xSe/ZnSe (x=0.2)," Li Wang and J. H. Simmons, Appl. Phys. Lett. 67, 1450-52 (1995).
8. "Growth, Doping and Electrical Contacts to ZnSe-Based Devices," P. H. Holloway, J. J. Fijol, L. C. Calhoun, K. S. Jones, J. H. Simmons, P. Zory and T. J. Anderson, in Proceedings of the 21st State-of-the-Art Program on Compound Semiconductors Vol 94-34, 2-11 (1995).
9. "Molecular Dynamics Study of Brittle Fracture in Silica Glass and Cristobalite", T. P Swiler, J. H. Simmons and A. C. Wright, J. Non-Crystalline Solids 182, 68-77 (1995).
10. "Carrier Dynamics Study of CdxZn1-xSe/ZnSe (x=0.2) Multiple Quantum Wells," L. Wang, J. H. Simmons, M. H. Jeon, R. M. Park and C. J. Stanton, J. Electron. Materials 25, 177-81 (1996).
11. "Quantum Confinement Effects on the Photoluminescence Spectra of CdTe Nanocrystals," O. R. Ochoa, C. Colajacomo, E. J. Witkowski, J. H. Simmons and B. G. Potter, Solid State Comm. 98, 717-21 (1996).
12. "Modeling of Absorption Data Complicated by Fabry-Perot Interference in Germanosilicate Thin Film Waveguides," K. Simmons-Potter and J. H. Simmons, J. Optical Soc. B 13, 268-272 (1996).
13. "Fundamental Issues in Automotive Veiling Glare," E. N. Boulos, R. Surowiec, J. L. Bomback, S. Subramanian, C. J. Simmons and J. H. Simmons, SAE Technical Paper 970227, February 1997.
14. "Viscous Shear Thinning During Glass Forming," J. H. Simmons and C. J. Simmons, Ceramic Technology International 1997, pp41-44 (1997).
15. Computational Modeling of Materials and Processing, J. H. Simmons, E. R. Fuller, A. L. Dragoo and E. J. Garboczi, eds., Creamic Transactions 69, The American Ceramic Society, Westerville, OH, 1997.
16. "Simulation of Surface Formation in Solids by Molecular Dynamics Fracture," J. H. Simmons, T. P. Swiler, Y. L. Tsai, J. J. Mecholsky and R. Bendale, in Computational Modeling of Materials and Processing, J. H. Simmons, E. R. Fuller, A. L. Dragoo and E. J. Garboczi, eds., Creamic Transactions 69, The American Ceramic Society, Westerville, OH, 1997, pp 61-68.
17. " Fractal Analysis of Glass and Crystals Using Molecular Dynamics," Y. L. Tsai, T. P. Swiler, J. H. Simmons and J. J. Mecholsky, Computational Modeling of Materials and Processing, J. H. Simmons, E. R. Fuller, A. L. Dragoo and E. J. Garboczi, eds., Creamic Transactions 69, The American Ceramic Society, Westerville, OH, 1997, pp 217-223.
18. “Structural and Dynamic Modeling of Mechanical Behavior of Solids” J. H. Simmons, J. Computer-Aided Mater. Design 4, 207 (1998).

PATENTS

1. P-1 "Fixation of Radioactive (Waste) Materials in a Glass Matrix," with P. B. Macedo, T. A. Litovitz. U. S. Patent 4,224,177, Sept. 1980.
2. P-2 "Joint Doped Porous Glass with High Modifier Concentrations," with P. B. Macedo, M. Samanta. U. S. Patent 4,183,620, Jan. 15, 1980 and U. S. Patent 4,299,608, Nov. 10, 1981.
3. P-3 "Method of Producing a Glass Article Having a Graded Refractive Index Profile of a Parabolic Nature," with S Murai, P. B. Macedo. U. S. Patent 4,302,231, Nov. 24, 1981.
4. P-4 "Immobilization of Radwastes in Glass Containers and Products Formed Thereby," with P. B. Macedo, C. J. Simmons, D. C. Tran, N. Lagakos. U. S. Patent 4,312,774, Jan. 1982.
5. P-5 "Fixation by Anion Exchange of Toxic Materials in a Glass Matrix," with D. C. Tran, P. B. Macedo, C. J. Simmons, N. Lagakos. U. S. Patent 4,333,847, June 1982
6. P-6 "Fixation by Ion-Exchange of Toxic Materials in a Glass Matrix," with C. J. Simmons, P. B. Macedo, T. A. Litovitz. U. S. Patent 4,469,628, Sept. 1984.
7. P-7 "Anti-Reflective Coating Comprising Light Metal Fluorides," with S. J. Pagano, E. M. Boulos and M. F. Best, U. S. Patent Application, June 1990.
8. P-8 "Multiple Coating for Anti-Reflection At Large Angles of Incidence," with R. Ochoa, E. M. Boulos and M. F. Best, U. S. Patent Application, May 1989 (issued 1992).
9. P-9 "Laser Dye Impregnated Silica Gels," with L. L. Hench, J. H. Simmons, B. F. Zhu and R. Ochoa, US Patent 5,357,667, October 18, 1994.
10. P10 "Process for Forming Anti-Reflective Coatings Comprising Light Metal Fluorides," with E. N. Boulos, M. F. Best and S. J. Pagano, US Patent 5,268,196, Dec. 7, 1994.
11. P11 "Anti-Reflective Coatings Comprising Light Metal Fluorides," with E. N. Boulos, M. F. Best and S. J. Pagano, US Patent 5,208,101 May 4, 1994.
12. P12 "Novel Design for the Fabrication of High Efficiency Solar Cells," Joseph H. Simmons, Patent Application.