Applied Surface Science, Vol.255, No.3, 775-777, 2008
Arrangement of metal phthalocyanines on Ge (001) 2 x 1 surfaces
For monolayer films of metal phthalocyanines deposited on the two-domain Ge (0 0 1) 2 x 1 surface, NEXAFS measurements indicate that the molecules are tilted at an angle of 24-26 degrees to the substrate. This result is further investigated here using NEXAFS and STM. First, the NEXAFS experiments previously carried out on the two-domain surface were repeated on a single domain Ge (0 0 1) 2 x 1 surface: it was found that NEXAFS perpendicular and parallel to the dimer rows were almost identical. Second, STM measurements indicate that most molecules adopt a unique bonding site, relative to the dimer rows and with the plane of the molecule parallel to the surface; however, some other bonding locations are also observed. Together these experiments suggest that a uniform molecular tilt is not an appropriate description; other possible explanations are briefly considered. (c) 2008 Elsevier B.V. All rights reserved.