Professor Gidley is involved in precision measurements of the singlet and triplet annihilation decay rates of the particle-antiparticle system called positronium. Comparison with calculations of these decay rates comprises a unique test of quantum electrodynamics. He has searched for exotic positronium decay modes as tests of fundamental conservation laws and discrete symmetries. His studies of metal surfaces and thin films include surface defects, film growth, and the generation and polarimetry of spin polarized low energy positron beams to probe surface magnetism. Professor Gidley is also using low energy positron beams to study surface, interface, and thin film properties of glassy polymers using depth-profiled positron lifetime spectroscopy in conjunction with traditional analysis techniques. His group is actively working with Sematech International and a host of industrial partners to develop a new positronium probe of nanoporous thin films. Such materials with engineered porosity at the nanometer scale are being intensely pursued by the microelectronics industry as next generation dielectrics in high-speed devices.
Professor Gidley is a Fellow of the American Physical Society.
Positron Annihilation as a Method to Characterize Porous Materials, (with H-g Peng and R. S. Vallery), Annual Review of Materials Research 36, 49 (2006).
Deducing Pore Structure and Growth Mechanisms in Porogen-templated Silsesquioxane Thin Films, (with H-g. Peng, R. S. Vallery, M. Liu, W. E. Frieze, J-H Yim, H-D Jeong, and J. Kim), Applied Phys. Lett. 87, 161903 (2005).
Resolution of the Orthopositronium-Lifetime Puzzle, (with R. S. Vallery and P. W. Zitzewitz), Phys. Rev. Lett. 90, 203402 (2003).
Determination of Pore-Size Distribution in Low-Dielectric Thin Films, (with W. E. Frieze, T. L. Dull, J. Sun, A. F. Yee, C. V. Nguyen, and D. Y. Yoon), Appl. Phys. Lett. 76, 1282 (2000).
Thermalization of Positronium in Gases, (with M. Skalsey, J. J. Engbrecht, R. K. Bithell, and R. S. Vallery), Phys. Rev. Lett. 80, 3727 (1998).
Interface and Surface Effects on the Glass Transition in Thin Polystyrene Films, (with G. B. DeMaggio, W. E. Frieze, M. Zhu, H. A. Hristov, and A. F. Yee), Phys. Rev. Lett. 78, 1524 (1997).
New Precision Measurement of the Decay Rate of Singlet Positronium, (with A. H. Al-Ramadhan), Phys. Rev. Lett. 72, 1632 (1994).
Direct Search for Two Photon Decay Modes of Orthopositronium, (with J. S. Nico and M. Skalsey), Phys. Rev. Lett. 66, 1302 (1991).
Reemitted Positron Spectroscopy of Thin Metal Films, (with W. E. Frieze), Phys. Rev. Lett. 60, 1193 (1988).
Spin Polarized Low Energy Positron Beams and Their Applications, (with A. Rich, J. Van House and P. W. Zitzewitz), Appl. Phys. A 43, 275 (1987).