The growth and ordering of C60 molecules on the WO2/W（110） surface have been studied by low-temperature scanning tunnelling microscopy and spectroscopy （STM and STS）, low-energy electron diffraction （LEED）, and ...The growth and ordering of C60 molecules on the WO2/W（110） surface have been studied by low-temperature scanning tunnelling microscopy and spectroscopy （STM and STS）, low-energy electron diffraction （LEED）, and density functional theory （DFT） calculations. The results indicate the growth of a well-ordered C60 layer on the WO2/W（110） surface in which the molecules form a close-packed hexagonal structure with a unit cell parameter equal to 0.95 nm. The nucleation of the C60 layer starts at the substrate＇s inner step edges. Low-temperature STM of C60 molecules performed at 78 K demonstrates well-resolved molecular orbitals within individual molecules. In the C60 monolayer on the WO2/W（110） surface, the molecules are aligned in one direction due to intermolecular interaction, as shown by the ordered molecular orbitals of individual C60. STS data obtained from the C60 monolayer on the WO2/W（110） surface are in good agreement with DFT calculations.展开更多
Writing at the nanoscale using the desorption of oxygen adatoms from the oxygen-rich MoO2＋x/Mo（110） surface is demonstrated by scanning tunnelling microscopy （STM）. High-temperature oxidation of the Mo（110） sur...Writing at the nanoscale using the desorption of oxygen adatoms from the oxygen-rich MoO2＋x/Mo（110） surface is demonstrated by scanning tunnelling microscopy （STM）. High-temperature oxidation of the Mo（110） surface results in a strained, bulk-like MOO2（010） ultra-thin film with an O-Mo-O trilayer structure. Due to the lattice mismatch between the Mo（110） and the MOO2（010）, the latter consists of well-ordered molybdenum oxide nanorows separated by 2.5 nm. The MoO2（010）/Mo（110） structure is confirmed by STM data and density functional theory calculations. Further oxidation results in the oxygen-rich MoOa^x/Mo（110） surface, which exhibits perfectly aligned double rows of oxygen adatoms, imaged by STM as bright protrusions. These adatoms can be removed from the surface by scanning （or pulsing） at positive sample biases greater than 1.5 V. Tip movement along the surface can be used for controlled lithography （or writing） at the nanoscale, with a minimum feature size of just 3 nm. By moving the STM tip in a predetermined fashion, information can be written and read by applying specific biases between the surface and the tip.展开更多
文摘The growth and ordering of C60 molecules on the WO2/W（110） surface have been studied by low-temperature scanning tunnelling microscopy and spectroscopy （STM and STS）, low-energy electron diffraction （LEED）, and density functional theory （DFT） calculations. The results indicate the growth of a well-ordered C60 layer on the WO2/W（110） surface in which the molecules form a close-packed hexagonal structure with a unit cell parameter equal to 0.95 nm. The nucleation of the C60 layer starts at the substrate＇s inner step edges. Low-temperature STM of C60 molecules performed at 78 K demonstrates well-resolved molecular orbitals within individual molecules. In the C60 monolayer on the WO2/W（110） surface, the molecules are aligned in one direction due to intermolecular interaction, as shown by the ordered molecular orbitals of individual C60. STS data obtained from the C60 monolayer on the WO2/W（110） surface are in good agreement with DFT calculations.
基金This work was supported by Science Foundation Ireland （Principal Investigator grant number 12/IA/1264, and Walton Visitor Award grant number 08/W.1/B2583）. A.N.C. acknowledges support of the 7th European Community Framework Programme. STM topographic images were processed using WSxM software [39].
文摘Writing at the nanoscale using the desorption of oxygen adatoms from the oxygen-rich MoO2＋x/Mo（110） surface is demonstrated by scanning tunnelling microscopy （STM）. High-temperature oxidation of the Mo（110） surface results in a strained, bulk-like MOO2（010） ultra-thin film with an O-Mo-O trilayer structure. Due to the lattice mismatch between the Mo（110） and the MOO2（010）, the latter consists of well-ordered molybdenum oxide nanorows separated by 2.5 nm. The MoO2（010）/Mo（110） structure is confirmed by STM data and density functional theory calculations. Further oxidation results in the oxygen-rich MoOa^x/Mo（110） surface, which exhibits perfectly aligned double rows of oxygen adatoms, imaged by STM as bright protrusions. These adatoms can be removed from the surface by scanning （or pulsing） at positive sample biases greater than 1.5 V. Tip movement along the surface can be used for controlled lithography （or writing） at the nanoscale, with a minimum feature size of just 3 nm. By moving the STM tip in a predetermined fashion, information can be written and read by applying specific biases between the surface and the tip.
