Growth of long range ordered pentacene/benzenethiol/Cu(100) heterostructure

We present a method of producing a long-range ordered pentacene ultra-thin film on a benzenethiol organic buffer layer at saturation coverage, deposited on a cleaned. single crystalline Cu(100) surface, by means of ultra-high-vacuum organic molecular beam epitaxy. The growth morphology is investigated using in-situ low-energy electron-diffraction (LEED) and high-resolution UV photoelectron spectroscopy (HR-UPS). The change in Surface symmetry from c(4x4) at low coverage to c(2 x 6)/c(2 x 2) at saturation coverage of benzenethiol has been examined by LEED. The corresponding valence band modifications have been found by HR-UPS. Pentacene layers Lip to a thickness of 0.6nni possess exactly the same symmetry of the beneath organic buffer layer at saturation coverage, but with more intense and sharper spots as observed in the LEED patterns.