Use of multi-wall carbon nanotubes as an absorber in a thermal detector

A thermopile based detector array has advantages when used for an infrared (IR) micro-spectrometer, as compared to an array of photon detector, such as flat spectral response and uncooled operation. A thermal detector requires a good absorber to achieve a high absorption coefficient in the spectral range of interest. Several solutions are available and the advantages and disadvantages are discussed. Multi-wall carbon nanotubes (CNTs) can be used as absorber with high absorption efficiency in IR band. Other advantages are high thermal conductivity and damage resistance which make them promising candidates as coatings for thermal detectors. This paper reports on nanotubes realized on a silicon substrate with titanium nitride thin film layer. Optical characterization is done using a commercially available spectrometer