Interface engineered carbon nanotubes with SiO₂ for flexible infrared detectors

Highlights: • Interface engineered carbon nanotubes with SiO₂ is used to construct a kind of flexible infrared detector. • The interface between the MWCNTs and SiO₂ could enhance the IR response speed. • Detector based on the integrated interface of MWCNTs and SiO₂ has successfully detected the movements of the human fingers. - Abstract: Nitrogen-doped/non-doped carbon nanotubes (CNTs) were integrated on SiO₂/Si and PMMA substrates for understanding the infrared sensing mechanisms. The nanotube structures on SiO₂ substrates exhibit a much shorter response time (about 40 ms) than those directly on PMMA substrates (about 1200 ms), indicating the interface effects between CNTs and the substrates. The infrared responses for both structures show a linear relationship with the light power density even at the radiation power as low as 0.1 mW/mm². Moreover, a new concept flexible IR detector was designed and fabricated by transferring the CNTs/SiO₂ structure onto the PMMA substrate, which exhibits both short response time (50 ms) and good flexibility. The successful detection of human finger movements indicates the practical applications of the CNT-based detectors for the detection of weak thermal or far infrared radiation.