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Palladium nanoparticles on InP for hydrogen detection.

Cernohorsky O, Zdansky K, Zavadil J, Kacerovsky P, Piksova K - Nanoscale Res Lett (2011)

Bottom Line: The size of the aggregates is dependent on the time of deposition.Forward and reverse I-V characteristics showed a high rectification ratio with a high Schottky barrier height.The response of the structure on the presence of hydrogen was monitored.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physical Electronics, Czech Technical University, V Holesovickach 2, Prague, Czeck Republic. cernohorsky@ufe.cz.

ABSTRACT
Layers of palladium (Pd) nanoparticles on indium phosphide (InP) were prepared by electrophoretic deposition from the colloid solution of Pd nanoparticles. Layers prepared by an opposite polarity of deposition showed different physical and morphological properties. Particles in solution are separated and, after deposition onto the InP surface, they form small aggregates. The size of the aggregates is dependent on the time of deposition. If the aggregates are small, the layer has no lateral conductance. Forward and reverse I-V characteristics showed a high rectification ratio with a high Schottky barrier height. The response of the structure on the presence of hydrogen was monitored.

No MeSH data available.


SEM images. (a) SEM image of PD nanolayers and (b) ND nanolayers
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Figure 1: SEM images. (a) SEM image of PD nanolayers and (b) ND nanolayers

Mentions: Secondary ion mass spectrometry (SIMS) spectra of Pd isotopes 104, 105, 106, 108, and 110 for the ND and PD layers showed that on PD layers, Pd content is about two orders of magnitude larger than in the ND layer. In Figure 1, SEM pictures of the PD and ND layers, respectively, prepared under the same conditions (66 V, 4 h), are presented. The density of the particles on the PD sample was larger while, in the case of the ND layer, small separated aggregates on the InP surface were observed. The PD sample exhibited charging in SEM; this is the reason we believe there are more nonconductive surfactant molecules which cover the majority of the InP surface. It suggests that surfactant aggregates without Pd particles are negatively charged in the solution, but the charging mechanism of nonpolar colloids is still far from clear. Because SEM observations of the particles from the colloid solution dropped on the TEM grid showed that the particles in the solution are not aggregated, it can be concluded that the particles form aggregates on InP during the electrophoretic deposition process.


Palladium nanoparticles on InP for hydrogen detection.

Cernohorsky O, Zdansky K, Zavadil J, Kacerovsky P, Piksova K - Nanoscale Res Lett (2011)

SEM images. (a) SEM image of PD nanolayers and (b) ND nanolayers
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211506&req=5

Figure 1: SEM images. (a) SEM image of PD nanolayers and (b) ND nanolayers
Mentions: Secondary ion mass spectrometry (SIMS) spectra of Pd isotopes 104, 105, 106, 108, and 110 for the ND and PD layers showed that on PD layers, Pd content is about two orders of magnitude larger than in the ND layer. In Figure 1, SEM pictures of the PD and ND layers, respectively, prepared under the same conditions (66 V, 4 h), are presented. The density of the particles on the PD sample was larger while, in the case of the ND layer, small separated aggregates on the InP surface were observed. The PD sample exhibited charging in SEM; this is the reason we believe there are more nonconductive surfactant molecules which cover the majority of the InP surface. It suggests that surfactant aggregates without Pd particles are negatively charged in the solution, but the charging mechanism of nonpolar colloids is still far from clear. Because SEM observations of the particles from the colloid solution dropped on the TEM grid showed that the particles in the solution are not aggregated, it can be concluded that the particles form aggregates on InP during the electrophoretic deposition process.

Bottom Line: The size of the aggregates is dependent on the time of deposition.Forward and reverse I-V characteristics showed a high rectification ratio with a high Schottky barrier height.The response of the structure on the presence of hydrogen was monitored.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physical Electronics, Czech Technical University, V Holesovickach 2, Prague, Czeck Republic. cernohorsky@ufe.cz.

ABSTRACT
Layers of palladium (Pd) nanoparticles on indium phosphide (InP) were prepared by electrophoretic deposition from the colloid solution of Pd nanoparticles. Layers prepared by an opposite polarity of deposition showed different physical and morphological properties. Particles in solution are separated and, after deposition onto the InP surface, they form small aggregates. The size of the aggregates is dependent on the time of deposition. If the aggregates are small, the layer has no lateral conductance. Forward and reverse I-V characteristics showed a high rectification ratio with a high Schottky barrier height. The response of the structure on the presence of hydrogen was monitored.

No MeSH data available.