Athanassiou, Evagelos K. and Mensing, Christian and Stark, Wendelin J. (2007) Insulator coated metal nanoparticles with a core/shell geometry exhibit a temperature sensitivity similar to advanced spinels. Sensors and Actuators A: Physical, 138 (1). 120 - 129.
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Official URL: http://www.sciencedirect.com/science/article/B6THG...
The preparation of carbon-coated copper nanoparticles with different carbon layers resulted in materials with a highly sensitive pressure and temperature dependent conductivity. The core/shell geometry of these carbon/metal composites afforded two distinctly different electrical behaviors depending on the carbon layer properties. Graphene layers with a predominant sp2 character showed an ill-defined bandgap structure as evidenced by UV–vis diffuse reflectance spectroscopy. The resulting composites were weak conductors with low sensitivity. Use of predominately insulating carbon layers with a well-defined bandgap of above 1.9 eV resulted in composites with a material constant β of over 4700 K which is comparable to currently used commercial spinels. A theoretical analysis and detailed material characterization by Raman spectroscopy, X-ray diffraction, 13C NMR spectroscopy and thermoanalysis suggested a tunneling based conduction mechanism in these core/shell materials. This interpretation was supported by a good correlation between experimental data and the estimated effects arising from the theoretical analysis of the tunneling effects.
|Uncontrolled Keywords:||Copper; Carbon; NTC; Sensor; Bandgap; Tunneling|
|Subjects:||Material Science > Nanofabrication processes and tools|
Analytical Science > Nanotechnology for sensing and actuating
Material Science > Nanostructured materials
|Deposited On:||24 Apr 2009 17:33|
|Last Modified:||24 Apr 2009 17:33|
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