NIPC SI(111)(7X7) STUDIED WITH XPS, STM AND TAPPING MODE AIR AFM/

We evaporated a few angstroms of nickel phthalocyanine (NiPC) in ultra high vacuum (UHV) on clean single crystal substrates of Si(111)(7 x 7) and studied in situ the structural and electronic properties of the i nterface with X-ray photoelectron spectroscopy (XPS) and scanning tunn eling microscopy (STM). The mesoscopic morphology of the samples has a lso been studied in air with a tapping mode atomic force microscope (T M-AFM). XPS measurements with variation of the NiPC thickness suggest planar adsorption of the first layer of admolecules; in particular, we found evidences for stronger chemisorption at the outer benzene rings of the PC molecule. UHV STM measurements confirm the XPS results; des pite the lack of intermolecular resolution we show an image suggesting chemisorption commensurate with the substrate lattice and planar stac king consistent with the intermolecular stacking in the known crystall ine phases of metal phthalocyanines. TM-AFM shows;a growth mode in ter ms of hat islands of 20-35 Angstrom, typical height and a few hundreds of nm width, The potential of imaging with TM-AFM elastic sample prop erties of soft materials deposited on hard substrates is addressed.