Direct formation of parallel single-walled carbon nanotube bridges on micromachined wide trenches for high-performance infrared sensors

We present the integration of super long horizontally aligned single-walled carbon nanotubes (SWNTs) on the micromachined wide trenches for infrared (IR) sensor application. The HA-SWNTs were found to be able to grow across trenches as wide as 1000 mum forming parallel SWNT bridges on the trench. The sensor fabricated with only one process shows sharp and remarkable responses to the ~ 4 mW IR radiations at 77 K. Its response to IR radiation of 120 Hz at room temperature in air could be easily observed. The response time constant, only ~500 mus, is more than 2 orders magnitude shorter than that of the reported IR sensors based on SWNT bundles, films and SWNT-polymer composites. It was believed to be achieved due to the absence of intertube junctions in our suspending parallel HA-SWNT bridges.