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Structural and thermal studies of silver nanoparticles and electrical transport study of their thin films.

Majeed Khan MA, Kumar S, Ahamed M, Alrokayan SA, Alsalhi MS - Nanoscale Res Lett (2011)

Bottom Line: The average grain size of silver nanoparticles is found to be 17.5 nm.The peaks in XRD pattern are in good agreement with that of face-centered-cubic form of metallic silver.The sample shows the activated variable range hopping in the localized states near the Fermi level.

View Article: PubMed Central - HTML - PubMed

Affiliation: King Abdullah Institute for Nanotechnology, King Saud University, Riyadh-11451, Saudi Arabia. majeed_phys@rediffmail.com.

ABSTRACT
This work reports the preparation and characterization of silver nanoparticles synthesized through wet chemical solution method and of silver films deposited by dip-coating method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and energy dispersive spectroscopy (EDX) have been used to characterize the prepared silver nanoparticles and thin film. The morphology and crystal structure of silver nanoparticles have been determined by FESEM, HRTEM, and FETEM. The average grain size of silver nanoparticles is found to be 17.5 nm. The peaks in XRD pattern are in good agreement with that of face-centered-cubic form of metallic silver. TGA/DTA results confirmed the weight loss and the exothermic reaction due to desorption of chemisorbed water. The temperature dependence of resistivity of silver thin film, determined in the temperature range of 100-300 K, exhibit semiconducting behavior of the sample. The sample shows the activated variable range hopping in the localized states near the Fermi level.

No MeSH data available.


Related in: MedlinePlus

Resistivity as function of temperature for thin film of silver nanoparticles. Inset shows the plot of ln ρ vs T-1/4.
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Figure 5: Resistivity as function of temperature for thin film of silver nanoparticles. Inset shows the plot of ln ρ vs T-1/4.

Mentions: The temperature dependence of dc electrical resistivity of thin films of silver nanoparticles in the temperature range 100-300 K has been shown in Figure 5. It is evident from the figure that the resistivity decreases with increase in temperature, which shows the semiconducting nature of the sample. In these semiconductors, there are additional energy levels in the band gap, which are localized and close to either the conduction or the valence band. Since the energy difference between these levels and band edges is very small, a slight thermal excitation is sufficient to accept or donate electrons; thereby the electrical resistivity decreases with increase in temperature. Electron transport in the nanocrystalline silver thin film at relatively low temperature could be explained by thermally activated hopping between localized states near the Fermi level. In the variable range hopping (VRH) process [33], it becomes favorable for an electron to jump from one localized state to another where the overlapping of wave functions exists. The difference in corresponding eigen energies is compensated by the absorption or emission of phonons. Thus, the variation of electrical resistivity with temperature can be described by three-dimensional Mott's variable range hopping model [34],


Structural and thermal studies of silver nanoparticles and electrical transport study of their thin films.

Majeed Khan MA, Kumar S, Ahamed M, Alrokayan SA, Alsalhi MS - Nanoscale Res Lett (2011)

Resistivity as function of temperature for thin film of silver nanoparticles. Inset shows the plot of ln ρ vs T-1/4.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211852&req=5

Figure 5: Resistivity as function of temperature for thin film of silver nanoparticles. Inset shows the plot of ln ρ vs T-1/4.
Mentions: The temperature dependence of dc electrical resistivity of thin films of silver nanoparticles in the temperature range 100-300 K has been shown in Figure 5. It is evident from the figure that the resistivity decreases with increase in temperature, which shows the semiconducting nature of the sample. In these semiconductors, there are additional energy levels in the band gap, which are localized and close to either the conduction or the valence band. Since the energy difference between these levels and band edges is very small, a slight thermal excitation is sufficient to accept or donate electrons; thereby the electrical resistivity decreases with increase in temperature. Electron transport in the nanocrystalline silver thin film at relatively low temperature could be explained by thermally activated hopping between localized states near the Fermi level. In the variable range hopping (VRH) process [33], it becomes favorable for an electron to jump from one localized state to another where the overlapping of wave functions exists. The difference in corresponding eigen energies is compensated by the absorption or emission of phonons. Thus, the variation of electrical resistivity with temperature can be described by three-dimensional Mott's variable range hopping model [34],

Bottom Line: The average grain size of silver nanoparticles is found to be 17.5 nm.The peaks in XRD pattern are in good agreement with that of face-centered-cubic form of metallic silver.The sample shows the activated variable range hopping in the localized states near the Fermi level.

View Article: PubMed Central - HTML - PubMed

Affiliation: King Abdullah Institute for Nanotechnology, King Saud University, Riyadh-11451, Saudi Arabia. majeed_phys@rediffmail.com.

ABSTRACT
This work reports the preparation and characterization of silver nanoparticles synthesized through wet chemical solution method and of silver films deposited by dip-coating method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and energy dispersive spectroscopy (EDX) have been used to characterize the prepared silver nanoparticles and thin film. The morphology and crystal structure of silver nanoparticles have been determined by FESEM, HRTEM, and FETEM. The average grain size of silver nanoparticles is found to be 17.5 nm. The peaks in XRD pattern are in good agreement with that of face-centered-cubic form of metallic silver. TGA/DTA results confirmed the weight loss and the exothermic reaction due to desorption of chemisorbed water. The temperature dependence of resistivity of silver thin film, determined in the temperature range of 100-300 K, exhibit semiconducting behavior of the sample. The sample shows the activated variable range hopping in the localized states near the Fermi level.

No MeSH data available.


Related in: MedlinePlus