Direct integration of carbon nanotubes on micromachined hotplates

This communication reports on the localized growth of carbon nanotubes (CNTs) on the surface of classical micro-hotplates with integrated heater and transducing electrodes. A catalytic thermal CVD process has been developed and adapted to grow CNTs by only using the heat provided by the integrated heater. Spatial control of the CNTs' growth was achieved thanks to this method; CNTs are localized only on the heating area of the micro-hotplate, and electrical contact with the integrated electrodes can be obtained. The influence of the catalyst, gas flow, and temperature cycles on the growth of CNT was investigated in order to optimize growth and avoid micro-hotplate degradation. Different strategies were investigated to get the electrical connection between the CNTs and the platinum electrodes. The electrically connected grown CNTs could be used directly as gas-sensitive resistors with superior performance in terms of sensitivity than metal—oxide gas sensors integrated on such platforms.