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Hydrogen sensors based on electrophoretically deposited Pd nanoparticles onto InP.

Grym J, Procházková O, Yatskiv R, Piksová K - Nanoscale Res Lett (2011)

Bottom Line: Electrophoretic deposition of palladium nanoparticles prepared by the reverse micelle technique onto InP substrates is addressed.Schottky diodes based on these films show notably high values of the barrier height and of the rectification ratio giving evidence of a small degree of the Fermi level pinning.Moreover, electrical characteristics of these diodes are exceptionally sensitive to the exposure to gas mixtures with small hydrogen content.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Photonics and Electronics, Academy of Sciences CR, v,v,i,, Prague 8, Czech Republic. grym@ufe.cz.

ABSTRACT
Electrophoretic deposition of palladium nanoparticles prepared by the reverse micelle technique onto InP substrates is addressed. We demonstrate that the substrate pre-deposition treatment and the deposition conditions can extensively influence the morphology of the deposited palladium nanoparticle films. Schottky diodes based on these films show notably high values of the barrier height and of the rectification ratio giving evidence of a small degree of the Fermi level pinning. Moreover, electrical characteristics of these diodes are exceptionally sensitive to the exposure to gas mixtures with small hydrogen content.

No MeSH data available.


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Current-voltage characteristics of the sample InP-Pd-07 showing the influence of post-deposition annealing on the forward and reverse characteristics.
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Figure 2: Current-voltage characteristics of the sample InP-Pd-07 showing the influence of post-deposition annealing on the forward and reverse characteristics.

Mentions: The first set included structures from Figure 1a, b, c, d. The high values of SBH of 0.84-0.87 eV-in comparison with thermally evaporated Pd reaching 0.45 eV only-indicated a very low degree of Fermi level pinning. The value of SBH did not substantially vary with the deposition conditions. The influence of post-deposition annealing was more significant. Figure 2 shows I-V curves of the sample InP-Pd-07 from Figure 1d before and after annealing. Both the SBH and the rectification ratio R (defined as a ratio of the forward and reverse current at a given voltage) are considerably decreased after annealing. This decrease is tentatively assigned to the damage of the uncovered parts of the InP substrate and must be further investigated in detail. First experiments with hydrogen detection testing were performed with a mixture of H2/N2 containing 20% of H2 (Figure 3). A rapid current increase characterized by the sensing response S = 7.4 × 105 is observed for the sample InP-Pd-07. S = (IH - Iair)/Iair, where IH is a saturation current under the exposure to hydrogen and Iair is the same for air. After annealing, the sensing response significantly drops to 0.29 × 102. The same structure was later tested for 0.1% of H2 showing S = 1.8 × 102.


Hydrogen sensors based on electrophoretically deposited Pd nanoparticles onto InP.

Grym J, Procházková O, Yatskiv R, Piksová K - Nanoscale Res Lett (2011)

Current-voltage characteristics of the sample InP-Pd-07 showing the influence of post-deposition annealing on the forward and reverse characteristics.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211486&req=5

Figure 2: Current-voltage characteristics of the sample InP-Pd-07 showing the influence of post-deposition annealing on the forward and reverse characteristics.
Mentions: The first set included structures from Figure 1a, b, c, d. The high values of SBH of 0.84-0.87 eV-in comparison with thermally evaporated Pd reaching 0.45 eV only-indicated a very low degree of Fermi level pinning. The value of SBH did not substantially vary with the deposition conditions. The influence of post-deposition annealing was more significant. Figure 2 shows I-V curves of the sample InP-Pd-07 from Figure 1d before and after annealing. Both the SBH and the rectification ratio R (defined as a ratio of the forward and reverse current at a given voltage) are considerably decreased after annealing. This decrease is tentatively assigned to the damage of the uncovered parts of the InP substrate and must be further investigated in detail. First experiments with hydrogen detection testing were performed with a mixture of H2/N2 containing 20% of H2 (Figure 3). A rapid current increase characterized by the sensing response S = 7.4 × 105 is observed for the sample InP-Pd-07. S = (IH - Iair)/Iair, where IH is a saturation current under the exposure to hydrogen and Iair is the same for air. After annealing, the sensing response significantly drops to 0.29 × 102. The same structure was later tested for 0.1% of H2 showing S = 1.8 × 102.

Bottom Line: Electrophoretic deposition of palladium nanoparticles prepared by the reverse micelle technique onto InP substrates is addressed.Schottky diodes based on these films show notably high values of the barrier height and of the rectification ratio giving evidence of a small degree of the Fermi level pinning.Moreover, electrical characteristics of these diodes are exceptionally sensitive to the exposure to gas mixtures with small hydrogen content.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Photonics and Electronics, Academy of Sciences CR, v,v,i,, Prague 8, Czech Republic. grym@ufe.cz.

ABSTRACT
Electrophoretic deposition of palladium nanoparticles prepared by the reverse micelle technique onto InP substrates is addressed. We demonstrate that the substrate pre-deposition treatment and the deposition conditions can extensively influence the morphology of the deposited palladium nanoparticle films. Schottky diodes based on these films show notably high values of the barrier height and of the rectification ratio giving evidence of a small degree of the Fermi level pinning. Moreover, electrical characteristics of these diodes are exceptionally sensitive to the exposure to gas mixtures with small hydrogen content.

No MeSH data available.


Related in: MedlinePlus