• B.S., 1969, Technion
• Ph.D., 1979, Technion

Research Interests:

Professor Vardeny is an experimental physicist interested in transient and steady state optical, electronic and spintronic properties of organic semiconductors in the time domain from femtoseconds to minutes. In his laboratory Prof. Vardeny synthesizes a variety of semiconducting polymers and grows various single crystals from ?-conjugated oligomers and molecules. Using a variety of pulsed laser excitations he studies the transient response of photoexcitations in doped and undoped semiconducting polymer films, molecular organic crystals, fullerenes, single walled nanotubes and dielectric and metallic photonic crystals. The transient response also include laser action in the form of amplified spontaneous emission, random lasers, and lasing in fabricated microcavities, including microring, microdisk, opal photonic crystals and asymmetric cavities that support chaotic ray behavior. The transient dynamic investigations are complemented using steady state optical measurements such as absorption, emission and photomodulation spectroscopies, as well as optical detected magnetic resonance, photoconductivity and Raman scattering spectroscopies. In addition, the charge and spin injection from external electrodes into organic semiconductors is also investigated using a variety of metallic, ferromagnetic, and half metallic electrodes. Also being studied is the nonlinear optical spectra of these materials using the technique of four-wave-mixing, Z-scan and two-photon-absorption. The optical studies also include a variety of organic photonic crystals made out of polymers and oligomers infiltrated into synthetic opals, as well as 2D and 3D metallic photonic crystals.

On a more applicative note, solid-state devices made out of the organic semiconductors, such as field-effect-transistors, organic light emitting diodes, organic photovoltaic cells, and spin-valve devices are engineered, fabricated and tested in the laboratory.

Selected Recent Publications

• "Two-Dimensional Electronic Excitations in Self-Assembled Conjugated Polymer Nanocrystals" (with R. Österbacka, C. P. An, and X. M. Jiang), Science 287, 838 (2000).
• "Formation Cross-Sections of Singlet and Triplet Excitons in π-Conjugated Polymers" (with M. Wohlgenannt et al.), Nature 409, 494 (2001).
• "A Boost for Fiber Optics," Z. V. Vardeny, Nature 416, 489 (2002).
• "Ultrafast Dynamics of Excitons and Solitons in Disubstituted Polyacetylene" (with O. J. Korovyanko, I. I. Gontia, T. Masuda, and K. Yoshino), Phys. Rev. B 67, 035114 (2003).
• "Conjugation-Length Dependence of Spin-Dependent Polaron Recombination in π-Conjugated Materials" (with M. Wohlgenannt, X. M. Jiang, and R. A. J. Janssen), Phys. Rev. Lett. 88, 197401 (2002).
• "Photoinduced Quantum Interference Antiresonances in &pi'-Conjugated Polymers" (with R. Österbacka, X. M. Jiang, C. P. An, and B. Horovitz), Phys. Rev. Lett. 88, 226401 (2002).
• "Universal Properties of Random Lasers" (with R. C. Polson, and M. E. Raikh), IEEE Quantum Electronics 9, 120 (2003).
• "Linear and Nonlinear Photoexcitation Dynamics in π-Conjugated Polymers" (with O. Epshtein, Y. Eichen, E. Ehrenfreund, and M. Wohlgenannt), Phys. Rev. Lett. 90, 046804 (2003).
• "Giant Magnetoresistance in Organic Spin-Valves" (with Z. H. Xiong, D. Wu, and J. Shi), Nature 427, 823 (2004).
• "Optical Studies of Metallic Dielectric Photonic Crystals" (with V. Kamaev,V. Kozhevnikov, P. B. Landon, and A. A. Zakhidov), Jour. of Appl. Phys. 95, 2947 (2004).
• "Optical and Magneto-Optical Studies of 2D Metallo-Dielectric Photonic Crystals on Cobalt Films" (with M. Diwekar, V. Kamaev, and J. Shi), Appl. Phys. Lett. 84, 3112 (2004).
• "Studies of Exciton Dynamics in Single-Walled Carbon Nanotubes" (with O.Korovyanko, C. X. Sheng, A. B. Dalton, and R. Baughman), Phys. Rev. Lett. 97, 017403 (2004).
• "Directional Emission from Asymmetric Microlaser resonators of π-Conjugated Polymers" (with R. C. Polson), Appl. Phys. Lett. (in press).