Han Huang

Electronic structures of CuPc on a Ag(110) surface

Copper phthalocyanines (CuPc) on a Ag(110) surface have been studied by ultraviolet photoemission spectroscopy (UPS). On depositing CuPc organic films, the features from the substrate 3d valence fade and four new features corresponding to the adsorbed molecules emerge at 1.68, 4.45, 6.36 and 9.20 eV below the Fermi level. These features shift in binding energy with increasing thickness of the organic films. In the case of a monolayer, angle-resolved UPS measurements suggest that the molecular plane is nearly parallel to the substrate. Further theoretical calculation indicates that the adsorption of CuPc on a hollow site is the most favourable configuration, and the separation between the adsorbate and the substrate is about 2.7 A.

Study on the interaction between tetracene and Cu(110) surface

The electronic structure of tetracene on Cu (110) surface has been studied by using ultraviolet photoemission spectroscopy (UPS). The emission features from the organic molecule are located from 1 to 10 eV below the Fermi level, and they shift in binding energy with increasing the coverage of the organic material. For the surface with multilayer of tetracene, six well-resolved features were found at 1.90, 3.40, 4.70, 5.95, 6.95, and 9.15 eV below the Fermi level, respectively. On the surface with a lower coverage of tetracene, angle-resolved UPS measurements suggest that the molecular plane is parallel to the substrate. Density functional theory calculation confirms the flat-lying adsorption mode and shows that the tetracene molecule prefers to be adsorbed on the long bridge site with its long axis in the [110] azimuth.

Perylene monolayer on the Ru(0001) surface

The growth of epitaxial monolayer of perylene on Ru(0001) was investigated by means of scanning tunneling microscopy (STM). The STM images showed a coexistence of the ordered phase with a 12×12 superstructure and the disordered phase in a monolayer of perylene on Ru(0001). In the disordered region, the perylene molecules are randomly distributed, and orientated uniformly with their long axis in the [1000] direction. For the ordered phase, a model of the Ru(0001)-(12×12)-8 perylene superstructure was proposed. The results indicate that the growth behavior of perylene on Ru(0001) is mainly controlled by laterally repulsive molecule-molecule interaction.

Coverage dependence of the structure of tetracene on Ag(110)

The ordered adsorption structures of tetracene on Ag(110) have been studied by low energy electron diffraction (LEED), scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. At a low coverage, as calibrated with LEED, both p(4 x 4) and c(8 x 4) ordered structures are simultaneously formed on an Ag(110) surface at room temperature. STM images suggest the molecular plane is parallel to the Ag surface with its long molecular axis aligned along the [001] azimuth. DFT optimization reveals a separation of 0.3 nm between the molecular plane and substrate surface while the center of the tetracene molecule is on the long bridge site. Increasing coverage slightly, a structure is formed while the adsorbed molecules maintain the flat-lying geometry with adjacent molecules alternating their height relative to the surface.

Transportation of molecules with a scanning tunneling microscope

Transportation of mass molecules from one metal surface to another has been achieved with scanning tunneling microscope tip at room temperature. With scanning monolayer of tetracene on Ag(110) surface, the molecules were removed gradually, leaving ordered stripes on the Ag surface; the ordered stripes are unidirectional nanoscopic molecular rows with a width of about 1.4nm. Scanning the clean Ru(101¯0) sample with the tip, previously adsorbed the tetracene molecules, caused an appearance of the molecules on the Ru surface. Short molecular strips with different widths from 4to20nm were drawn on the Ru surface by a molecule-loaded W tip.

Study of the initial adsorption state of tetracene on

Tetracene on the [Formula: see text] surface has been investigated by ultraviolet photoemission spectroscopy (UPS). The UPS results show features, from tetracene, between 2.0 and 10.0xa0eV below the Fermi level, and their shift in binding energy with increasing coverage. Angle-resolved UPS (ARUPS) results indicate that the molecular plane of tetracene near the interface is parallel to the substrate. Moreover, an abxa0initio calculation has also been carried out to determine the favourable adsorption structure. Temperature-dependent UPS measurements show that tetracene is stable on the [Formula: see text] surface up to 150u2009°C.

Study of the initial adsorption state of tetracene on \mathrm {Ru}(10\bar {1}0)

Tetracene on the [Formula: see text] surface has been investigated by ultraviolet photoemission spectroscopy (UPS). The UPS results show features, from tetracene, between 2.0 and 10.0xa0eV below the Fermi level, and their shift in binding energy with increasing coverage. Angle-resolved UPS (ARUPS) results indicate that the molecular plane of tetracene near the interface is parallel to the substrate. Moreover, an abxa0initio calculation has also been carried out to determine the favourable adsorption structure. Temperature-dependent UPS measurements show that tetracene is stable on the [Formula: see text] surface up to 150u2009°C.

Study of the initial adsorption state of tetracene on [Formula: see text].

Tetracene on the [Formula: see text] surface has been investigated by ultraviolet photoemission spectroscopy (UPS). The UPS results show features, from tetracene, between 2.0 and 10.0xa0eV below the Fermi level, and their shift in binding energy with increasing coverage. Angle-resolved UPS (ARUPS) results indicate that the molecular plane of tetracene near the interface is parallel to the substrate. Moreover, an abxa0initio calculation has also been carried out to determine the favourable adsorption structure. Temperature-dependent UPS measurements show that tetracene is stable on the [Formula: see text] surface up to 150u2009°C.