Reid Chesterfield DuPont Corporation Ph.D. Chemical Engineering, 2004

Molecular organic materials have recently experienced a surge of research interest because of their potential application as flexible, large-area semiconductors.  My research focuses on the morphology and electrical properties of thin films and single crystals of these materials.  Charge carrier mobility is an intrinsic electrical property that is used to characterize semiconductors.  I use three experimental techniques for studying the mobility of these materials: field effect transistor (FET) measurements, space charge injection spectroscopy (SCIS), and time-of-flight (TOF).  I investigate their morphology with x-ray diffraction, optical microscopy, and atomic force microscopy.  By connecting morphology and mobility, I hope to discern the conduction mechanism of a material in order to provide insight into the design of new materials.  The effect of electrode contacts, grain boundaries, and electrical traps is not well understood in molecular organic materials and is of utmost importance for realizing devices.  In addition, I am interested in the device parameters associated with the FET structure, specifically threshold voltage and on/off current ratio.

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.

"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).

"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 19281-19292.

"Variable Temperature Film and Contact Resistance Measurements on Operating n-channel Organic Thin Film Transistors", Chesterfield, R. J.; McKeen, J. C.; Newman, C. R.; Frisbie, C. D.; Ewbank, P. C.; Mann, K. R.; Miller, L. L., J. Appl. Phys. 2004, 95, 6396-6405.

"Transport Properties of Single-Crystal Tetracene Field-Effect Transistors with Silicon Dioxide Gate Dielectric," Newman, C. R.; Chesterfield, R. J.; Merlo, J. A.; Frisbie, C. D., Appl. Phys. Lett. 2004, 85, 422-424.

"High Electron Mobility and Ambipolar Transport in Organic Thin Film Transistors Based on a p-Stacking Quinoidal Terthiophene", Chesterfield, R.J.; Pappenfus, T.M.; Newman, C.R.; Ewbank, Paul C.; Haukaas, M.; Mann, K.R.; Miller, L.L; C.D. Frisbie; Advanced Materials 2003 15, 1278-1282.

"A pi-Stacking Terthiophene-Based Quinodimethane is an n-Channel Conductor in a Thin Film Transistor", Pappenfus, T.M.; Chesterfield, R.J.; Frisbie, C.D.; Mann, K.R.; Casado, J.; Raff, J.D.; Miller, L.L.; J. Am. Chem. Soc. 2002, 124(16), 4184-4185.

"Hydrostatic Pressure Dependence of the Photoconductivity of Single Crystal Pentacene and Tetracene", Rang, Z.; Haraldsson, A.; Kim, D.M.; Chesterfield, R.J.; Frisbie, C.D.; Ruden, P.P.; Nathan, M.I.; Appl. Phys. Lett. 2001, 79, 2731.