Fabrication of Aligned Carbon Nanocoil Thermal Sensor With a High Temperature Coefficient of Electrical Resistance at 25–100 °C

This paper presents a novel thermal sensor using carbon nanocoils (CNCs) as sensing elements with a high-temperature coefficient of electrical resistance (TCR) at 25-100 °C. CNCs have been synthesized at 700 °C using Fe-Sn catalytic solution by chemical vapor deposition from acetylene. The as-grown CNC has a coil diameter of 200-1500 nm, a pitch of 100-1000 nm, and a fiber diameter of 80-550 nm. The CNC thermal sensor was fabricated in four types in this paper: bulk CNCs, a single CNC, multiple CNCs, and bundled CNCs. The thermal sensors of CNCs were measured in a furnace to evaluate the TCR of the thermal sensor at 25-100 °C. It was found that the TCR of thermal sensors of CNCs was distributed from -0.12%/°C to -1.12%/°C, depending on different sensing elements. The stabilizing contact resistance between CNCs and electrodes was improved by annealing. The high TCR values of thermal sensors of CNCs suggest the Schottky contact with the interface of CNCs and electrode after annealing.