0000000000680101
AUTHOR
M. Petukhov
showing 14 related works from this author
Fluorinated Fullerene Molecule on Cu(001) Surface as a Controllable Source of Fluorine Atoms
2018
A coverage-dependent growth of well-ordered copper halogenide structures as a result of fluorinated fullerene molecule adsorption on Cu(001) surface has been studied by means of scanning tunneling ...
Experimental and theoretical evidence for substitutional molybdenum atoms in theTiO2(110)subsurface
2006
Molybdenum was deposited at room temperature on the ${\mathrm{TiO}}_{2}(110)$ surface in the 0--1.3 equivalent monolayer (eqML) range and was then annealed at $400\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ in order to reach a kind of equilibrium state. A threshold was found in the behavior of the deposit: below 0.2 eqML, substitutional molybdenum occurs in titanium sites located under the bridging oxygen atoms of the ${\mathrm{TiO}}_{2}(110)$ surface. In this position, molybdenum atoms are in a structural and chemical ${\mathrm{MoO}}_{2}$-like environment. Density-functional theory calculations show that this molybdenum site is actually the most stable one in …
Interaction of Mo(CO) 6 and its derivative fragments with the Cu(001) surface: Influence on the decomposition process
2014
A theoretical study on the adsorption and decomposition of molybdenum carbonyl on the copper (001) surface is reported. The adsorption structures and energies of Mo(CO)n molecules (n = 1 … 6) are computed systematically using density functional theory with Van der Waals corrections. By analyzing the energies of the various conformations, the main factors that determine the stable adsorption geometry are identified. Insight into the thermodynamics of decomposition is gained by calculating the reaction energy for dissociation of Mo(CO)n into Mo(CO)n−1 and CO. In the gas phase, this reaction is highly endothermic for all n. On the Cu surface, however, removal of the first CO group (n = 6) beco…
Field-induced tip–sample oxygen transfer in scanning tunneling microscopy on TiO2(110) (1 1).
2008
International audience; A study on the field-induced tip–surface oxygen transfer at room temperature and its influence on the tunneling conditions for stable STM imaging of the TiO2(110) (1 1) surface is reported. A simple model of field-induced transfer is applied to tungsten and platinum–iridium tips. The oxygen transition rates from the sample to the tip or from the tip to the sample depend on the oxygen desorption barriers formed at tunneling distance. For stable imaging the applied bias voltage has to balance the oxygen transfer probabilities in both directions. In the case of Pt/Ir tips, the tunneling conditions for images with clear evidence of bridging oxygen point defects have been…
Tunneling induced decomposition of Mo(CO)(6) onto TiO2(110) surface
2012
International audience; Tunneling induced decomposition of Mo(CO)(6) from the gas phase was studied on TiO2(110) surface by scanning tunneling microscopy (STM) and spectroscopy (STS). The efficiency of the procedure was followed by measuring the dot volume as a proportional indicator of the amount of the decomposed precursor. It was found that below 1 x 10(-5) Pa background pressure of Mo(CO)(6), there is no measurable effect and above 1 x 10(-4) Pa, the nanodot size is too large compared to the curvature of the tip (20-40 nm). A threshold bias of +3.1(+/- 0.1) V on the sample was measured for the decomposition of Mo(CO)(6) in gas ambient. In the absence of the precursor, dot formation was …
Monolayer Formation of Molybdenum Carbonyl on Cu(111) Revealed by Scanning Tunneling Microscopy and Density Functional Theory
2012
International audience; Molybdenum carbonyl Mo(CO)(6) was adsorbed on the Cu(111) surface at 160 K in the monolayer coverage range and studied by scanning tunneling microscopy. A well-ordered monolayer of hexacarbonyl molecules was observed experimentally for the first time. The monolayer has a hexagonal structure compatible with a (root 7 x root 7)R19 superlattice on the copper (111) plane. The arrangement and orientation of the molecules on the surface were determined by density functional theory calculations, including van der Waals interactions. The comparison of adsorption and cohesive energies reveals that the molecule-substrate interaction is stronger than the intermolecular one, whi…
Scanning tunneling microscopy and spectroscopy of Mo clusters grown on TiO2(110).
2007
Molybdenum was deposited in two steps (3 eq. ML and 1 eq. ML) on the light blue rutile TiO2 10) (1 x 1) surface at room temperature, each Mo deposition cycle being followed by an annealing up to 950-1000 K. This procedure was found to lead to formation of separated clusters having a size in very wide range (1-20 nm). Scanning tunneling microscopy showed a dependence of the cluster morphology as a function of the size. The scanning tunneling spectra of Mo clusters was studied as a function of cluster dimensions and discussed in comparison with photoelectron spectroscopy results previously obtained for homogeneous Mo films. The dI/d V curves do not display the valence band structure of deposi…
Fluorination of Cu(001) Surface by C60F48 Molecule Adsorption
2019
Copper surface functionalization by defluorination of C60F48 molecules with submonolayer and monolayer coverages on the Cu(001) crystal is studied by X-ray photoelectron spectroscopy. At room tempe...
Mo(CO)6 dissociation on Cu(111) stimulated by a Scanning Tunneling Microscope
2013
Abstract The surface of Cu(111) was exposed to molybdenum hexacarbonyl Mo(CO)6 with monolayer coverage at temperature 160 K and studied by a Scanning Tunneling Microscope. The monolayer structure has a hexagonal arrangement and forms a (√7 × √7) R19 superlattice on the copper (111) plane. Upon repeated scanning the monolayer is transformed into a (1 × 2) superstructure with 3-fold oriented domains. The domains of (1 × 2) superstructure can change orientation under scanning according to 3-fold surface symmetry. From analysis of the domain mobility, it follows that CO groups of carbonyl fragments are organized in the (1 × 2) superstructure conditioning the domain reorientation. The observed s…
Molybdenum thin film growth on a TiO2 (1 1 0) substrate.
2009
International audience; We report a first principles study on the structure and energetics of thin films of molybdenum on a (1 1 0) surface of rutile TiO2. Mo films with 1 × 1 epitaxy in the coverage range between 0.5 and 2 monolayer are investigated. The most stable structures are those which maximize the number of Mo–Mo bonds. This leads to two-dimensional structures with zigzag Mo–Mo coordination for 1 monolayer coverage and three-dimensional structures with approximately body-centered cubic coordination for higher coverage. For a coverage up to 1.5 monolayers, the interface Mo atoms preferentially occupy the so-called upper hollow adsorption site with three Mo–O bonds
Epitaxial growth of molybdenum on TiO2(110)
2003
Abstract Molybdenum was deposited on blue (i.e. non-stoichiometric) TiO2(1 1 0) surface using a very low deposition rate (less than 0.05 eqML min−1). The resulting deposit was investigated by means of X-ray photoelectron diffraction (XPD), LEED and XPS. Just after deposition, the film is mainly constituted of metallic molybdenum, contains oxygen homogeneously dispersed through the whole deposit and the broad features detected in XPD scans are interpreted as a coarse epitaxy between TiO2(1 1 0) surface and the (0 0 1) face of bcc molybdenum. The orientation relationship is: Mo(1 0 0)[0 0 1]//TiO2(1 1 0)[0 0 1]. After annealing the deposit at 673 K, XPD scans become sharper and epitaxy is ach…
Strong Bonding of Single C60 Molecules to (1 × 2)-Pt(110): an STM/DFT Investigation.
2007
International audience; The interaction of single C60 molecules with the (1 × 2)-Pt(110) surface has been studied by scanning tunneling microscopy and density functional theory (DFT) calculations on slab models. Molecules are observed to be frozen at room temperature and are found to be almost exclusively in the same configuration. Extensive DFT calculations show that this configuration is the global energy minimum, suggesting that adsorbed molecules have enough rototranslational freedom to escape from the numerous local minima. The adsorption energy (3.81 eV) is the strongest ever found for C60, and it is roughly proportional to the number of the Pt and C atoms at contact distance. Analysi…
Growth of tungsten nanostructures on TiO2 (110) by decomposition of metalorganic precursor. Reactivity towards oxygen.
2007
Communication orale
Growth of supported nanostructures on TiO2 (110) by soft CVD.
2007
Communication orale