AVS 45th International Symposium
    Organic Electronic Materials Topical Conference Tuesday Sessions
       Session OE+AS+EM-TuM

Paper OE+AS+EM-TuM9
Tapping Mode Near-Field Scanning Optical Microscopy of Molecular Crystals and Thin Films

Tuesday, November 3, 1998, 11:00 am, Room 327

Session: Organic Thin Film Interfaces
Presenter: H. Stadniychuk, University of Minnesota
Authors: H. Stadniychuk, University of Minnesota
A. Kosterin, University of Minnesota
C.D. Frisbie, University of Minnesota
Correspondent: Click to Email
We describe near-field optical imaging experiments to probe fluorescence and birefringence in molecular crystals and polymeric thin films. These experiments utilize a near-field microscope that employs tapping mode feedback to scan the sample underneath a cantilevered optical fiber probe, facilitating imaging of soft organic samples. In one set of studies, we have focussed on fluorescence and transmission imaging of 30-400 nm thick crystals of tetracene grown by vacuum sublimation onto transparent substrates. These well-defined crystals are excellent samples for investigating quantitative aspects of near-field imaging, and we seek to determine the spatial extent of the near-field by quantifying the relationship between fluorescence intensity and crystallite thickness. A second set of studies exploits polarization modulation techniques to investigate birefringence from thin films of polymers, such as polyethylene oxide. A key aspect of these investigations is comparison of the near-field birefringence images with birefringence images obtained by confocal microscopy. This comparison facilitates understanding of contrast mechanisms in near-field characterization of organic thin films.