AVS 50th International Symposium
    Surface Science Wednesday Sessions
       Session SS+OF-WeA

Paper SS+OF-WeA1
Electronic and Geometric Structures of Pentacene Molecules Grown on Au(100)

Wednesday, November 5, 2003, 2:00 pm, Room 327

Session: Growth and Characterization of Organic Films
Presenter: Y.J. Song, Seoul National University, Korea
Authors: Y.J. Song, Seoul National University, Korea
K. Lee, Seoul National University, Korea
J. Yu, Seoul National University, Korea
Y. Kuk, Seoul National University, Korea
Correspondent: Click to Email
A pentacene molecule has attracted much interest for its possible application to organic-based electronic devices with its interesting electronic properties. Despite reported semiconducting property of the bulk crystal, it is hard to grow the high-quality film. Here, we report our scanning tunneling microscopy studies on the geometric and electronic structures of pentacene molecular layers on a Au(100) surface. Because of the high diffusivity of the molecule at room temperature, the STM studies were done at low temperature. At submonolayer coverage, the molecules are confined to the troughs of the reconstructed Au(100)-(5x20), forming a chain structure perpendicular to the reconstrcted ridges. We resolved the HOMO and LUMO states of pentacene molecules on a Au(100) surface with atomic resolution. The DFT (density functional theory) results of the molecular layer reveal good agreement with the observed gerometric and electronic structures. The electronic levels of pentacene molecules are shifted in the presence of metallic substrate. This result can be valuable when one makes metal-pentacene junctions for device applications. The electronic levels are also shifted with pentacene-pentacene interactions. At the coverages higher than 2 monolayers, a single phase was observed. The pentacene-pentacene interaction plays a important roll to the growth structures. The 5 pentacene molecules work as a base unit for the multilayer film. The correlation between the growth structure and the transport property will be discussed.