DETERMINATION OF 2-DIMENSIONAL STRUCTURES OF ULTRATHIN FILMS OF H-2-PHTHALOCYANINE AND CU-PHTHALOCYANINE ON MOS2 BY ANGLE-RESOLVED ULTRAVIOLET PHOTOEMISSION AND LOW-ENERGY-ELECTRON DIFFRACTION

The angle-resolved ultraviolet photoelectron spectra of ultrathin film s of metal-free phthalocyanine (H(2)Pc) and copper phthalocyanine (CuP c) on MoS2 single crystal surfaces were measured using synchrotron rad iation. The take-off and azimuthal angle dependencies of the photoelec tron intensity were analyzed using independent-atomic-center approxima tion combined with molecular orbital calculation. Further, the low ene rgy electron diffraction was observed for the same ultrathin films. Th e results indicate that H(2)Pc and CuPc molecules form a square lattic e with respect to the three equivalent crystal axes of the MoS2 surfac e, and at the lattice point lie flat on the substrate with a molecular azimuthal rotation of about 7 degrees.