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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.


Related in: MedlinePlus

Current-voltage characteristic. Dependence of current on time of the ND Pd layer on InP interface in the presence of the 0.1% H2/N2 mixture. A forward bias of 0.1 V was applied.
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Figure 3: Current-voltage characteristic. Dependence of current on time of the ND Pd layer on InP interface in the presence of the 0.1% H2/N2 mixture. A forward bias of 0.1 V was applied.

Mentions: Formerly, we assumed that the PD layers were better for sensing because of their higher content of Pd. The response of these layers, equipped with silver contacts, to the presence of hydrogen was very quick, but the current change was not very high because of the impenetrability of the silver contact for the hydrogen molecules. The current change was more than two orders of magnitude. Now, we use graphite contacts, which are porous, and ND layers with lower density of coverage, so at the places, where are no Pd nanoparticles, the graphite contact touches the surface. The response of the structure on 0.1% H2 in N2 mixture can be seen in Figure 3. The current change was of 55,000 × when the current increased from its initial value 4.2 × 10-10 A to 2.3 × 10-5 A. The response and recovery times are of the order of 10 s, but the full recovery to its original value, probably due to the slow release of hydrogen diffused into the crystal lattice of the Pd nanoparticles, takes about 10 h [4].


Palladium nanoparticles on InP for hydrogen detection.

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

Current-voltage characteristic. Dependence of current on time of the ND Pd layer on InP interface in the presence of the 0.1% H2/N2 mixture. A forward bias of 0.1 V was applied.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Current-voltage characteristic. Dependence of current on time of the ND Pd layer on InP interface in the presence of the 0.1% H2/N2 mixture. A forward bias of 0.1 V was applied.
Mentions: Formerly, we assumed that the PD layers were better for sensing because of their higher content of Pd. The response of these layers, equipped with silver contacts, to the presence of hydrogen was very quick, but the current change was not very high because of the impenetrability of the silver contact for the hydrogen molecules. The current change was more than two orders of magnitude. Now, we use graphite contacts, which are porous, and ND layers with lower density of coverage, so at the places, where are no Pd nanoparticles, the graphite contact touches the surface. The response of the structure on 0.1% H2 in N2 mixture can be seen in Figure 3. The current change was of 55,000 × when the current increased from its initial value 4.2 × 10-10 A to 2.3 × 10-5 A. The response and recovery times are of the order of 10 s, but the full recovery to its original value, probably due to the slow release of hydrogen diffused into the crystal lattice of the Pd nanoparticles, takes about 10 h [4].

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.


Related in: MedlinePlus