A Study on the Temperature Sensitivity of Nanosensors Based on Single-Walled Carbon Nanotubes in Ambient Conditions

Electron transport in nonisolated carbon nanotubes (CNTs) is highly influenced by their interactions with their environment. In this study, the effect of the local surroundings on the temperature sensitivity of single-walled CNTs is investigated at ambient temperature. For this study, CNTs are trapped in between two nanoelectrodes on a sapphire substrate using a dielectrophoretic trapping process. We find that it is possible to tune the temperature sensitivity by controlling the number of trapped nanotubes. The results indicate that the temperature sensitivity increases as the number of nanotubes decreases. For a device fabricated with a few CNTs, resistance changes at a rate of 3.24%/°C, but the sensitivity of devices with many CNTs is significantly smaller with a resistance change of 0.19%/°C. We attribute this effect to changes in the interaction of the sapphire substrate with changes in the CNTs' concentration.