Professor
Departments of Physics and Applied Physics & Applied Math
ap359@columbia.edu
Pinczuk Webpage

Research Interests

Pentacene is a leading contender as a material for next generation microelectronics and optoelectronics. In our studies of pentacene we have demonstrated that intrinsic optical recombination (intrinsic luminescence) and resonance Raman light scattering methods that probe intra-molecular and inter-molecular vibrations are venues to study physics of interface layers and monolayers. The optical methods developed in this research provide flexible, easy-to-use tools that could be used in nanoscale structures of organic molecular semiconductors. Benchmarks of this research are the optical studies of monolayers of pentacene deposited on SiO2 surfaces that are functionalized by coating with poly a-methylstyrene (PAMS) to promote p-p stacking interactions. Such monolayers have superior properties because they are ultra-uniform. In these superb layers we succeeded in the first detection of intrinsic luminescence, and the first observations of lattice modes (phonons) of monolayers by Raman scattering. These findings demonstrate how optics studies probe physics, materials properties and device characteristics of organic semiconductors at the nanoscale.

Selected Publications

• R. He, N. G. Tassi, G. B. Blanchet, and A. Pinczuk, “Probing high quality pentacene monolayers by optical methods”, Physica E 32, 589-591 (2006).
• R. He, X. Chi, A. Pinczuk, D.V. Lang, and A.P. Ramirez, “Extrinsic optical recombination in pentacene single crystals: Evidence of gap states”, Appl. Phys. Lett. 87, 211117/1-3 (2005).
• R. He, N. G. Stassi, G. B. Blanchet and A. Pinczuk, “Fundamental optical recombination in pentacene clusters and ultra-thin films”, Appl. Phys. Lett. 87, 103107/1-3 (2005).
• R. He, I. Dujovne, L. Chen, Q. Miao, C. Hirjibehedin, A. Pinczuk, C. Nuckolls, C. Kloc and G. B. Blanchet “Probing nanoscale pentacene films by resonant Raman scattering”, contributed paper at the 27th International Conference on the Physics of Semiconductors (2005).
• R. He, I. Dujovne, L.W. Chen, Q. Miao, C.F. Hirjibehedin, A. Pinczuk, C. Nuckolls, C. Kloc, A. Ron, “Resonant Raman scattering in nanoscale pentacene films”, Appl. Phys. Lett. 84, 987-989 (2004).