The study of carbon nanotubes as coating films for electrically calibrated detectors

Abstract

A UV electrically calibrated pyroelectric detector is developed in this paper which was used to establish an electrically calibrated system for high-accuracy UV radiometric calibration. A single crystal of (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN-PT), as one of the best pyroelectric materials, was selected as the detector material. Research on the coating film on the surface of the sensitive area was carried out. A carbon nanotube (CNT) film was selected as the coating material. The UV reflectivity of samples with the sheet resistance from 100 to 150 Ω is in the range of 1.6–4.2%, and the highest reflectivity is in the vicinity of 265 nm. Both the UV radiant heating and the electrical heating in the CNT film can result in a temperature change. Accordingly, the film can work both as an optical absorber and as an electric heater. By means of this, the measurement of UV radiation power can be converted to the measurement of electrical power. The uniformity of the detector was studied; the typical nonuniformity is less than 2% in the active region of the ϕ8 mm optical absorption. The responsivity of the detector is about 18.3 V W−1 at 14 Hz, 365 nm.