C. Daniel Frisbie Group
Chemical Engineering & Materials Science
University of Minnesota - Twin Cities
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Films & Interfaces,
Molecular Crystals,
Molecular Electronics,
Organic Semiconductors,
Scanning Probe Microscopy
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Sandy Fritz Vos
Azdel, Inc.
Ph.D. Materials Science, 2006
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Transport Properties of Organic Semiconductor Materials Correlated to Film Microstructure Development at the
Organic-Dielectric Interface
The relationship between molecular structure and transport properties of organic semiconductor materials is an important goal for the future of organic electronics. In order to probe the transport properties of pentacene and other organic semicondutors, our research group fabricates organic thin film transistors (OTFTs). For this device configuration, charged carrier transport is believed to occur within the first few monolayers of the organic material at the dielectric interface. It is therefore critical to understand the initial stages of film growth, molecular structure and interface properties. I am currently investigating how the dielectric surface roughness and chemistry affect organic film growth and the resulting transport properties in an OTFT. In order to characterize various dielectric surfaces and organic films, I utilize Atomic Force Microscopy to observe dielectric roughness and cleanliness, the initial stages of film growth and bulk film morphology. I also characterize the structure of my films by X-ray diffraction. A recent collaboration with Mike Wards research group here in the department and Michael Toney at the Stanford Linear Accelerator Center is allowing us to obtain Grazing Incidence X-ray Diffraction data with Synchrotron radiation in order to probe in-plane lattice parameters of a pentacene film on an amorphous SiO2 dielectric, or the active channel region of an OTFT. I am also investigating the use of Capacitance-Voltage measurements for characterization of semiconductor-insulator interfaces to complement our groupsEpresent techniques. The underlying goal of my research is to manipulate the organic-dielectric interface such that we may begin to understand and control transport properties of an organic semiconductor material for various materials systems and applications.
Publications
"Effect of Dielectric Roughness on Performance of Pentacene TFTs and Restoration of Performance with a Polymeric Smoothing Layer," Fritz, S. E.; Kelley, T. W.; Frisbie, C. D., J. Phys. Chem. B 2005, 109 10574.
"P-Channel Organic Semiconductors Based on Hybrid Acene-Thiophene Molecules for Thin-Film Transistor Applications," 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. Am. Chem. Soc. 2005, 127 3997.
"Structural Characterization of a Pentacene Monolayer on an Amorphous SiO2 Substrate with Grazing Incidence X-ray Diffraction," Fritz, S. E.; Martin, S .M.; Frisbie, C. D.; Ward, M. D.; Toney, M. F., J. Am. Chem. Soc. 2004, 126 4084.
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