Single-Walled Carbon Nanotube Thermopile for Broadband Light Detection

We designed a thermopile based on a PN doping pro!le engineered in a suspended film of single-walled carbon nanotubes (SWNTs). Using estimates of the film local Seebeck coeffcients, the SWNT thermopile was optimized in situ through depositions of potassium dopants. The overall performances of the thermopile were found to be comparable to state-of-the-art SWNT bolometers. The device is characterized at room temperature by a time response of 36 ms, typical of thermal detectors, and an optimum spectral detectivity of 2 x 10⁶ cm Hz^1/2/W in the visible and near-infrared. This paper presents the first thermopile made of a suspended SWNT film and paves the way to new applications such as broadband light (including THz) detection and thermoelectric power generation.