Characterization of suspended single-walled carbon nanotube film formed by ac dielectrophoresis for infrared sensing applications

A suspended single-walled carbon nanotube (SWNT) film was formed by alternating current dielectrophoresis on a silicon cavity and its electrical and optical characteristics were investigated for infrared (IR) sensing application. This study shows that a suspended SWNT film with an active detector area of 15 μm×3 μm functioned well as a bolometer. The fabricated SWNT-based bolometer was characterized by measuring the current-voltage curve, response time, resistance change with variation in temperature, optical responsivity, time-dependent reliability in responsivity, and detectivity in order to verify the performance of the IR detection. The experimental results showed that the fabricated bolometer had the appropriate IR-sensitive properties with a response time of ∼10 ms and a temperature coefficient of resistance (TCR) of -1.19%/K. Particularly, the bolometer had a reasonable responsivity of 2.96×10⁵ mV/W compared to conventional bolometers based on SWNTs and good time-dependent reliability during the experimental period.