Near-infrared response of a single carbon nanocoil

Abstract

The near-infrared photoresponse of a single suspended carbon nanocoil (CNC) is investigated. Under the irradiation of a 785 nm laser beam, the photoresponse is generated in the voltage-biased CNC. At a voltage of 50 mV, the ratio of the conductance change to the initial conductance, which is defined as the sensitivity in this paper, can reach 22% and the typical response time is 5 ms. It is found from the changes of photoresponse with pressure and with the laser power that the photoresponse of the CNC is mainly attributed to the bolometric effect. Because of the increase of Joule heating, the sensitivity reduces with the elevation of the bias voltage. However, the responsivity increases with the increase of the bias voltage, which is opposite to the change of the sensitivity. The maximum responsivity of the single CNC IR sensor is 0.22 A W⁻¹.