C. Daniel Frisbie Group
Chemical Engineering & Materials Science
University of Minnesota - Twin Cities 		Films & Interfaces,
Molecular Crystals,
Molecular Electronics,
Organic Semiconductors,
Scanning Probe Microscopy

Chris Newman Chris Newman
University of Cambridge, UK
Ph.D. Chemical Engineering, 2005

Electrical Properties of Organic Single Crystals

One of the most important considerations for the electrical characterization of semiconductors (inorganic and organic alike) is material purity, since very small amounts of residual impurity can dramatically affect electrical properties. I use gradient sublimation as a technique to purify the novel compounds we work with, and I use this same technique to grow large-area single crystals of these same materials, both for structural analysis and device fabrication. Although thin-film devices are a more immediate practical application of organic semiconductors, the underlying physics associated with these materials can only be investigated in the absence of grain boundaries. We characterize these single-crystal devices either in a 2-terminal (space-charge limited current (SCLC) spectroscopy) or 3-terminal (field effect transistor, also with additional channel probes for the investigation of contact effects) geometry. In addition to device fabrication and characterization, I am also involved in writing the algorithms for analyzing the current-voltage data we acquire and in modeling the behavior of these devices.

Publications

"High Mobility Top-Gated Pentacene Thin-Film Transistors," Newman, C. R.; Chesterfield, R. J.; Panzer, M. J.; Frisbie, C. D., J. Appl. Phys. 2005, 98 084506.

"Introduction to Organic Thin Film Transistors and Design of n-Channel Organic Semiconductors," Newman, C. R.; Frisbie, C. D.; da Silva Filho, D. A.; Bredas, J. L.; Ewbank, P. C.; Mann, K. R., Chem. Mater. 2004, 16 4436.

"Transport Properties of Single-Crystal Tetracene Field-Effect Transistors with Silicon Dioxide Gate Dielectric," Newman, C. R.; C., R. J.; Merlo, J. A.; Frisbie, C. D., Appl. Phys. Lett. 2004, 85 422.

"Atmospheric Stability of Perylene Diimide OTFTs," Newman, C. R.; Merlo, J. A.; Frisbie, C. D., (in preparation)

"Comparison of Top- and Bottom-Gated Pentacene Thin Film Transistors," Newman, C. R.; Merlo, J. A.; Frisbie, C. D., (in preparation)

"Gated Four-Probe Measurements on Pentacene Thin Film Transistors: Contact Resistance as a Function of Gate Voltage and Temperature," Pesavento, P. V.; Chesterfield, R. J.; Newman, C. R.; Frisbie, C. D., J. Appl. Phys. 2004, 96 7312.

"Organic thin Film Transistors Based on N-Alkyl Perylene Diimides: Charge Transport Kinetics as a Function of Gate Voltage and Temperature," Chesterfield, R. J.; McKeen, J. C.; Newman, C. R.; Ewbank, P. C.; da Silva Filho, D. A.; Bredas, J. L.; Miller, L. L.; Mann, K. R.; Frisbie, C. D., J. Phys. Chem. B. 2004, 108 19281.

"Variable temperature film and contact resistance measurements on operating n-channel organic thin film transistors," Chesterfield, Reid J.; McKeen, John C.; Newman, Christopher R.; Frisbie, C. Daniel; Ewbank, Paul C.; Mann, Kent R.; Miller, Larry L., J. App. Phys. 2004, 95 6396.

"Organic Thin Film Transistors Based on Tolyl-Substituted Oligothiophenes," Mohapatra, S.; Holmes, B. T.; Newman, C. R.; Prendergast, C. F.; Frisbie, C. D.; Ward, M. D., Adv. Func. Mat. 2004, 14 605.

"High Electron Mobility and Ambipolar Transport in Organic Thin-Film Transistors Based on a pi-Stacking Quinoidal Terthiophene," Chesterfield, R. J.; Newman, C. R.; Pappenfus, T. M.; Ewbank, P. C.; Haukaas, M. H.; Mann, K. R.; Miller, L. L.; Frisbie, C. D., Adv. Mat. 2003, 15 1278.

"Pentacene Organic Field Effect Transistor on Metal Substrates with Spin-Coated Smoothing Layer," Jin, Y.; Rang, Z.; Nathan, M. I.; Newman, C. R.; Frisbie, C. D., Appl. Phys. Lett. 2004, 85 4406.

"New p-Channel Organic Semiconductors Based on Hybrid Acene-Thiophene Molecules," Merlo, J. A.; Newman, C. R.; Gerlach, C. P.; Kelley, T. W., Muyres, D. V.; Fritz, S. E.; Toney, M. F.; Frisbie, C. D., J. Amer. Chem. Soc. (in press)

"Low-Voltage Operation of a Pentacene Field-Effect Transistor with a Polymer Electrolyte Gate Dielectric," Panzer, M. J.; Newman, C. R.; Frisbie, C. D., Appl. Phys. Lett. 2005, 86 103503.

"Hydrostatic pressure dependence of charge carrier transport in single crystal rubrene devices," Rang, Z.; Nathan, M. I.; Ruden, P. P.; Podzorov, V.; Gershenson, M. E.; Newman, C. R.; Frisbie, C. D., (in press)

"Ambipolar Transport in Heterostructured Organic Thin Film Transistors," Mohapatra, S.; Merlo, J. A.; Holmes, B. T.; Newman, C. R.; Chesterfield, R. J.; Frisbie, C. D.; Ward, M. D., J. Phys. Chem. B. (submitted)

"Charge Carrier Transport in Field Effect Transistors Based on Tricyanovinyl-capped Oligothiophenes," Cai, X.; Burand, M.; Newman, C. R.; Mann, K. R.; Frisbie, C. D., (in preparation)

"Modeling the Ultraviolet Photodegradation of Rigid Polyurethane Foams," Newman, C. R.; Forciniti, D., Ind. Eng. Chem. Res. 2001, 40 3346.

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