0000000000240019
AUTHOR
Gian Andrea Rizzi
Experimental and theoretical evidence for substitutional molybdenum atoms in theTiO2(110)subsurface
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 …
Scanning tunneling microscopy and spectroscopy of Mo clusters grown on TiO2(110).
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…
Epitaxial growth of molybdenum on TiO2(110)
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…