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Geoffrey P. Summers

Professor

Dean of the College of Natural and Mathematical Sciences

D.Phil, Oxford University, 1969

Postdoctoral work at University of North Carolina at Chapel Hill.

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Contact Information
Office of the Dean
UC 116, University Center
Univ. Maryland Baltimore County
1000 Hilltop Circle
Baltimore, MD 21250
Phone: (410) 455-5827
Email: gsummers@umbc.edu

Research Interests

Efficient operation of electronic devices depends on the controlled inclusion of dopant atoms, and on the elimination of unwanted impurities and structural defects in the constituent semiconductors. Semiconductor devices used in earth satellites, however, are subjected to irradiation by particles in the Van Allen belts, which degrade their performance by introducing radiation-induced defects. Understanding the properties of radiation-induced defects in semiconductors is therefore essential in optimizimg the survivability of space electronics as well as being an interesting part of materials research.

Deep level transient spectroscopy (DLTS) is a powerful tool for studying defect properties in semiconductor junctions such as those found in solar cells and other devices, and can be used to measure defect introduction rates, annealing kinetics, and other important properties. When used with other techniques such as the Hall effect, DLTS can give detailed information about the effect of defects on the electrical properties of semiconductors.

Recent research has concentrated on the properties of radiation-induced defects in III-V semiconductors such as InP, GaAs, and combinations of these materials which are important in photonic devices and space photovoltaic systems. The research is performed in collaboration with workers at several outside institutions including the Naval Research Laboratory, the National Renewable Energy Laboratory, and industrial research laboratories.

Selected Publications

Radiation Response and Injection Annealing of p+n InGaP Solar Cells
R.J. Walters, M.A. Xapsos, H.L. Cotal, S.R. Messenger, G.P. Summers, P.R. Sharps and M.L. Timmons,
1998, Solid State Electronics .
The Probability of Large Solar Proton Events and their Effect of the Efficiency of GaAs Solar Cells
M.A. Zapsos, S.R. Messenger, R.J. Walters, G.P. Summers and E.A. Burke,
1998, Progress in Photovoltaics 5.
Proton Displacement and Ionizing Damage Dose for Shielded Devices in Space
S.R. Messenger, M.A. Zapsos, E.A. Burke and G.P. Summers,
1997, IEEE Trans. on Nucl. Sci. 44 2169-2173
Low Energy Proton-Induced Displacement Damage in Shielded GaAs Solar Cells in Space
G.P. Summers, S.R. Messenger, E.A. Burke, M.A. Zapsos and R.J. Walters,
1997, Appl. Phys. Letters 71, 832-834.
Role of Radiation-Hard Solar Cells in Minimizing the Costs of Global Satellite Communication Systems
G.P. Summers, R.J. Walters, S.R. Messenger and E.A. Burke,
1996, Progress in Photovoltaics Research and Applications 4,147-154
Annealing of Irradiated Epitaxial InP Solar Cells
R.J. Walters, S.R. Messenger, H.L. Cotal and G.P. Summers,
1996, J. Appl. Phys. 80, 4315-4321
Displacement Damage Analogs to Ionization Dose
G.P. Summers, E.A. Burke and M.A. Xapsos,
1995, Radiation Measurements 24, 1-8
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