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(4$\times $4) at low coverage to c($2\times 6$)/c($2\times 2$) at saturation coverage of benzenethiol has been examined by LEED. The corresponding valence band modifications have been found by HR-UPS. Pentacene layers up to a thickness of 0.6 nm 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