Simultaneous Growth of MWCNTs at Different Temperatures in a Variable Gradient Furnace

Valentina Grossi; Ale Urbani; Andrea Giugni; C. Cantalini; Sandro Santucci; Maurizio Passacantando

doi:10.4028/www.scientific.net/SSP.154.77

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Performance of Shape Memory Composite with SMA and SMP
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Shape Memory Assemblies Using Ultrasonic Welding
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Simultaneous Growth of MWCNTs at Different Temperatures in a Variable Gradient Furnace
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Nano-Silicon Sol-Gel Film Refraction Index Modulation with Femtosecond Laser
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Simultaneous Growth of MWCNTs at Different Temperatures in a Variable Gradient Furnace

Abstract:

Multi-walled carbon nanotubes (MWCNTs) have been grown, simultaneously at different temperatures (600 °C, 700 °C, 725 °C, and 750 °C), by thermal chemical vapour deposition (CVD) of acetylene (C2H2) gas, in ammonia (NH3) atmosphere. The samples have been characterized morphologically by scanning electron microscopy (SEM) and a structurally by Raman spectroscopy. These analyses show that, when the temperature of substrate increases, the CNT average diameter and the density distribution decrease, and the CNTs are less defective. However there is a temperature limit (725 °C) for CNT growth. We have grown CNTs onto Si3N4/Si substrates with Pt electrodes, in order to realize the gas sensing devices. The CNTs grown at 725 °C, exhibit a fast response and a high sensitivity to NO2 gas.