NiPC/Si(111)(7 × 7) STUDIED WITH XPS, STM AND TAPPING MODE AIR AFM

1997 ◽  
Vol 04 (01) ◽  
pp. 59-64 ◽  
Author(s):  
L. OTTAVIANO ◽  
S. di Nardo ◽  
L. LOZZI ◽  
M. PASSACANTANDO ◽  
P. PICOZZI ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Soft Materials ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Metal Phthalocyanines ◽  
Tapping Mode ◽  
Nickel Phthalocyanine ◽  
Atomic Force ◽  
Structural And Electronic Properties

We evaporated a few angstroms of nickel phthalocyanine (NiPC) in ultrahigh vacuum (UHV) on clean single crystal substrates of Si (111)(7×7) and studied in situ the structural and electronic properties of the interface with X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). The mesoscopic morphology of the samples has also been studied in air with a tapping mode atomic force microscope (TM-AFM). XPS measurements with variation of the NiPC thickness suggest planar adsorption of the first layer of admolecules; in particular, we found evidences for stronger chemisorption at the outer benzene rings of the PC molecule. UHV STM measurements confirm the XPS results; despite the lack of intermolecular resolution we show an image suggesting chemisorption commensurate with the substrate lattice and planar stacking consistent with the intermolecular stacking in the known crystalline phases of metal phthalocyanines. TM-AFM shows a growth mode in terms of flat islands of 20–35 Å typical height and a few hundreds of nm width. The potential of imaging with TM-AFM elastic sample properties of soft materials deposited on hard substrates is addressed.

scholarly journals Characterization of Uranium Particles Produced via Pulsed Laser Deposition

2003 ◽  
Vol 802 ◽  
Author(s):  
S. C. Glade ◽  
T. W. Trelenberg ◽  
J. G. Tobin ◽  
A. V. Hamza
Keyword(s):  
Pulsed Laser Deposition ◽  
Photoelectron Spectroscopy ◽  
Pulsed Laser ◽  
Scanning Tunneling Spectroscopy ◽  
Laser Deposition ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Gaseous Species ◽  
Experimental Apparatus

ABSTRACTWe have constructed an experimental apparatus for the synthesis (via pulsed laser deposition) and analysis of nanoparticles and thin films of plutonium and other actinides. In-situ analysis techniques include x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning tunneling microscopy (STM), and scanning tunneling spectroscopy (STS). Also, the oxidation kinetics and the reaction kinetics of actinides with other gaseous species can be studied with this experimental apparatus. Preliminary results on depleted uranium are presented.

Anodic oxidation of Au(111)

1997 ◽  
Vol 75 (11) ◽  
pp. 1703-1709 ◽  
Author(s):  
Marie Anne Schneeweiss ◽  
Dieter M. Kolb ◽  
Dezhong Liu ◽  
Daniel Mandler
Keyword(s):  
Atomic Force Microscopy ◽  
Scanning Tunneling Microscopy ◽  
Anodic Oxidation ◽  
Exchange Process ◽  
Oxide Phase ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force

The initial stages of the anodic oxidation of Au(111) were investigated by means of cyclic voltammetry as well as in situ scanning tunneling microscopy (STM). The results suggest that the place exchange process, which initiates the oxide formation, starts at step edges. The oxide phase was imaged in situ by scanning tunneling and atomic force microscopy (AFM). The topographic information acquired by the two techniques is compared. Keywords: gold, gold oxide, corrosion, scanning tunneling microscopy (STM), atomic force microscopy (AFM).

scholarly journals Electron transfer between anatase TiO2 and an O2 molecule directly observed by atomic force microscopy

2017 ◽  
Vol 114 (13) ◽  
pp. E2556-E2562 ◽  
Author(s):  
Martin Setvin ◽  
Jan Hulva ◽  
Gareth S. Parkinson ◽  
Michael Schmid ◽  
Ulrike Diebold
Keyword(s):  
Atomic Force Microscopy ◽  
Electron Transfer ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Near Surface ◽  
Force Microscopy ◽  
Atomic Force

Activation of molecular oxygen is a key step in converting fuels into energy, but there is precious little experimental insight into how the process proceeds at the atomic scale. Here, we show that a combined atomic force microscopy/scanning tunneling microscopy (AFM/STM) experiment can both distinguish neutral O2 molecules in the triplet state from negatively charged (O2)− radicals and charge and discharge the molecules at will. By measuring the chemical forces above the different species adsorbed on an anatase TiO2 surface, we show that the tip-generated (O2)− radicals are identical to those created when (i) an O2 molecule accepts an electron from a near-surface dopant or (ii) when a photo-generated electron is transferred following irradiation of the anatase sample with UV light. Kelvin probe spectroscopy measurements indicate that electron transfer between the TiO2 and the adsorbed molecules is governed by competition between electron affinity of the physisorbed (triplet) O2 and band bending induced by the (O2)− radicals. Temperature–programmed desorption and X-ray photoelectron spectroscopy data provide information about thermal stability of the species, and confirm the chemical identification inferred from AFM/STM.

scholarly journals Oxidation of uranium nanoparticles produced via pulsed laser ablation

2005 ◽  
Vol 893 ◽  
Author(s):  
Tom Trelenberg ◽  
Stephen C Glade ◽  
James G Tobin ◽  
Thomas E Felter ◽  
Alex V Hamza
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metallic Nanoparticles ◽  
Pulsed Laser ◽  
Scanning Tunneling ◽  
Residual Water ◽  
Tunneling Microscopy ◽  
Nanosecond Pulses ◽  
Langmuir Kinetics ◽  
Experimental Apparatus

AbstractAn experimental apparatus designed for the synthesis, via pulsed laser deposition, and analysis of metallic nanoparticles and thin films of plutonium and other actinides was tested on depleted uranium samples. Five nanosecond pulses from a Nd:YAG laser produced films of ∼1600 Å thickness that were deposited showing an angular distribution typical of thermal ablation. The films remained contiguous for many months in vacuum but blistered due to induced tensile stresses several days after exposure to air. The films were allowed to oxidize from the residual water vapor within the chamber (2×10-10 Torr base pressure). The oxidation was monitored by in-situ analysis techniques including x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and scanning tunneling microscopy (STM) and followed Langmuir kinetics.

RECENT DEVELOPMENTS IN ALKALI METAL INTERCALATION OF LAYERED TRANSITION METAL DICHALCOGENIDES

2000 ◽  
Vol 14 (13) ◽  
pp. 455-471 ◽  
Author(s):  
H. I. STARNBERG
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Alkali Metals ◽  
Transition Metal Dichalcogenides ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Recent Developments ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

The modification of layered transition metal dichalcogenides through intercalation is reviewed, with special emphasis on in situ intercalation with alkali metals. Experimental results obtained using photoelectron spectroscopy, low-energy electron diffraction, scanning tunneling microscopy and transmission electron microscopy are presented, and conclusions about the in situ intercalation process and the associated crystallographic and electronic structure changes are presented. It is stressed that various kinds of defects and disorders must be taken into account for a full understanding.

Scanning Tunneling Microscopy and Atomic Force Microscopy of Au Implanted in Highly Oriented Pyrolytic Graphite

1995 ◽  
Vol 396 ◽  
Author(s):  
Y S. Tung ◽  
A. Ueda ◽  
D.O. Henderson ◽  
R. Mu ◽  
Z. Gu ◽  
...  
Keyword(s):  
Pyrolytic Graphite ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Highly Oriented Pyrolytic Graphite ◽  
Tunneling Microscopy ◽  
Gold Colloids ◽  
Tapping Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Tapping Mode Afm

AbstractSurfaces of highly oriented pyrolytic graphite implanted with gold were studied by both constant current STM. constant force, and tapping mode AFM. Gold colloids were observed by both constant current STM and tapping mode AFM. The surfaces can be modified by applying currents of +4 V and 1 nA. In addition, pyramidal and faceted structures were observed on sample surfaces suggesting the presence of diamond microcrystals.

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