AVS 52nd International Symposium
    Electronic Materials and Processing Friday Sessions
       Session EM-FrM

Paper EM-FrM9
Pentacene Wetting Layer Formation on SiO@sub 2@ Substrate

Friday, November 4, 2005, 11:00 am, Room 309

Session: Organic Electronic Devices
Presenter: D. Jeon, Seoul National University, South Korea
Authors: C. Kim, Seoul National University, South Korea
D. Jeon, Seoul National University, South Korea
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We have applied in-situ ellipsometry to study the growth of pentacene film on the SiO@sub 2@ surface. As soon as the evaporation began, the intensity of ellipsometry spectrum decreased. Atomic force microscopy (AFM) images of the early stage of growth, however, did not show any pentacene-related morphology. The pentacene islands in the first layer appeared after a continued deposition. The immediate change of ellipsometry spectrum with the onset of deposition indicates that pentacene molecules accumulate on the SiO@sub 2@ surface from the beginning. However, the flat AFM image of the early stage indicates that pentacene initially forms an amorphous wetting layer before crystalline islands appear. The roughness of the SiO@sub 2@ surface decreased with the pentacene deposition, which is another indication of the amorphous wetting layer. Pentacene is known to form a wetting layer on a clean metal or semiconductor substrate. In other words, pentacene reacts with the surface before a crystalline film forms. Our result shows that pentacene forms a wetting layer on an inert substrate as well. The existence of an amorphous layer on an insulating substrate should affect the performance of the pentacene devices. To show this we will also present the result from the electrostatic force microscopy of the pentacene film. This work was supported by the Nano Systems Institute at Seoul National University.