Pulsed Laser Deposition and In Situ Scanning Tunneling Microscopy of Pd clusters supported on alumina

2011 ◽  
Vol 1351 ◽  
Author(s):  
C.S. Casari ◽  
S. Foglio ◽  
M. Corbetta ◽  
M. Passoni ◽  
C.E. Bottani ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Pulsed Laser Deposition ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Ultra High Vacuum ◽  
Laser Deposition ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Pd Clusters

ABSTRACTWith the aim of addressing the material gap issue between model and real systems in heterogeneous catalysis, we exploited Pulsed Laser Deposition (PLD) to produce Pd clusters supported on ultrathin alumina films (Pd/Al2O3/NiAl(001) and Pd/Al2O3-x/HOPG). The structural properties have been investigated by in situ Scanning Tunneling Microscopy (STM) in ultra high vacuum (UHV). At first, Pd clusters were deposited by evaporation and by PLD on Al2O3 surfaces grown by thermal oxidation of NiAl(001). The system shows thermal stability up to 650 K. By PLD we deposited Pd clusters with a good size control obtained by varying the background gas pressure and the target-to-substrate distance. We then realized aPd/Al2O3-x/HOPG system where both Pd clusters and the alumina film are produced by PLD showing that, by exploiting the same deposition technique, it is possible to synthesize both a model system addressable by in situ STM and a thick film (∼100 μm) closer to realistic systems.

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.

scholarly journals Annealing Condition Effects on the Structural Properties of FePt Nanoparticles Embedded in MgO via Pulsed Laser Deposition

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 131
Author(s):  
Tingting Xiao ◽  
Qi Yang ◽  
Jian Yu ◽  
Zhengwei Xiong ◽  
Weidong Wu
Keyword(s):  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Annealing Process ◽  
Ultra High Vacuum ◽  
Laser Deposition ◽  
Fept Nanoparticles ◽  
Annealing Conditions ◽  
Vacuum Atmosphere

FePt nanoparticles (NPs) were embedded into a single-crystal MgO host by pulsed laser deposition (PLD). It was found that its phase, microstructures and physical properties were strongly dependent on annealing conditions. Annealing induced a remarkable morphology variation in order to decrease its total free energy. H2/Ar (95% Ar + 5% H2) significantly improved the L10 ordering of FePt NPs, making magnetic coercivity reach 37 KOe at room temperature. However, the samples annealing at H2/Ar, O2, and vacuum all showed the presence of iron oxide even with the coverage of MgO. MgO matrix could restrain the particles’ coalescence effectively but can hardly avoid the oxidation of Fe since it is extremely sensitive to oxygen under the high-temperature annealing process. This study demonstrated that it is essential to anneal FePt in a high-purity reducing or ultra-high vacuum atmosphere in order to eliminate the influence of oxygen.

Using a Moderate Vacuum, Hot/Cryo-Stage Equipped AFM for In-Situ Observation of α-Phase Growth In 60SN40PB Hypoeutectic Solder

1998 ◽  
Vol 4 (S2) ◽  
pp. 316-317
Author(s):  
D. N. Leonard ◽  
P.E. Russell
Keyword(s):  
Surface Science ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
In Situ Observation ◽  
Atmospheric Conditions ◽  
Tunneling Microscopy ◽  
Wide Range ◽  
Gas Environment

Atomic force microscopy (AFM) was introduced in 1984, and proved to be more versatile than scanning tunneling microscopy (STM) due to the AFM's capabilities to scan non-conductive samples under atmospheric conditions and achieve atomic resolution. Ultra high vacuum (UHV) AFM has been used in surface science applications when control of oxidation and corrosion of a sample's surface are required. Expensive equipment and time consuming sample exchanges are two drawbacks of the UHV AFM system that limit its use. Until recently, no hot/cryo-stage, moderate vacuum, controlled gas environment AFM was commonly available.We have demonstrated that phase transformations are easily observable in metal alloys and polymers with the use of a moderate vacuum AFM that has in-situ heating/cooling capabilities and quick (within minutes) sample exchange times. This talk will describe the results of experiments involving a wide range of samples designed to make use of the full capabilities of a hot/cryo-stage, controlled gas environment AFM.

Scanning Tunneling Microscopy Observation Of Single Dangling Bonds on the Si(100)2×1:H Surface

2001 ◽  
Vol 705 ◽  
Author(s):  
Lequn Liu ◽  
Jixin Yu ◽  
Joseph W. Lyding
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Negative Charge ◽  
High Vacuum ◽  
Surface Current ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Dangling Bonds ◽  
Tunneling Microscopy ◽  
Current Image ◽  
P Type

AbstractThe electrical properties of single dangling bonds on the Si(100)2×1:H surface are investigated by ultra high vacuum scanning tunneling microscopy. On the N-type Si(100)2×1:H surface, single dangling bonds created by feedback controlled lithography and natural dangling bonds have a fixed negative charge. On the other hand, they are observed as neutral on the P-type Si(100)2×1:H surface. Current image tunneling spectroscopy is used to characterize both types of dangling bonds. The dangling bonds with fixed negative charge display a dramatic voltage dependence with Friedel oscillations observed in the empty state images. The neutral dangling bonds appear as protrusions in both the empty and filled state images.

Sign in / Sign up

Export Citation Format

Share Document