AVS 47th International Symposium
    Organic Films and Devices Wednesday Sessions
       Session OF+EL+SS-WeM

Paper OF+EL+SS-WeM3
Grain Boundary Effects on Electrical Transport in Polycrystalline Organic Semiconductor Thin Films

Wednesday, October 4, 2000, 9:00 am, Room 313

Session: Transport and Device Issues in Organic Thin Films
Presenter: R.J. Chesterfield, University of Minnesota
Authors: R.J. Chesterfield, University of Minnesota
A.B. Chwang, University of Minnesota
K. Puntambekar, University of Minnesota
C.D. Frisbie, University of Minnesota
Correspondent: Click to Email
The role of microstructure in electrical transport in polycrystalline thin films of organic semiconducting oligomers (e.g., pentacene, sexithiophene) has not been extensively explored. This talk describes experiments in which transport through single grain boundaries (GBs) is probed using field effect transistor (FET) structures and Kelvin probe force microscopy (KPFM). In the FET studies, closely spaced gold source and drain electrodes are connected to pairs of pentacene or sexithiophene microcrystals grown on insulating substrates, such as SiO@sub 2@. The microcrystals, or grains, share a common boundary that dominates the transport through the FET. Conduction through the GB is measured as a function of gate field and temperature, and the results are compared with a recent model by Schon and Batlogg.@footnote 1@) In the KPFM studies, a metal-coated AFM tip is used to record potential distributions across an operating microcrystal FET. The resulting images reveal where the voltage is dropped across the device and thus point to the chief bottlenecks in the current transport. In general, both the microcrystal FET and Kelvin probe experiments show that microstructure, and in particular GBs, can potentially dominate transport in polycrystalline organic semiconductor films. @FootnoteText@ @footnote 1@J. H. Schon, B. Batlogg, Appl. Phys. Letters, 74(2), 1999, 260-262.