Sensitivity Enhancement of Photothermoelectric Terahertz Detectors with Series Combination between Carbon Nanotubes and Metals

This paper presents highly flexible terahertz (THz) detectors based on single-walled carbon nanotube (SWNT) films. Based on detection mechanism of the photothermoelectric effect, the effective Seebeck coefficient between the SWNT film and the electrode metal is a key parameter for sensitive THz detection. We proposed and demonstrated that the effective Seebeck coefficient was increased by employing the combination with the electrode in series, and achieved raising the sensitivity of THz detection. Particularly utilizing metals (nickel, bismuth) with negative Seebeck coefficient for the series electrode led to the sensitivity enhancement by a factor of 17 times compared to conventional parallel combination.