Infrared (IR) radiation detecting and sensing systems using aligned or bundled carbon nanotubes and methods to making the same. In certain embodiments of the invention, it includes a substrate, aligned or bundled carbon nanotubes, first and second conducting interconnects each in electrical communication with the nanotubes. Bundled nanotubes can be tuned to increase the temperature coefficient of resistance to increase sensitivity to IR radiation. In addition bundled nanotubes are independent of Nyquist frequency limitations found in other IR sensors because of the lack of 1/f or flicker noise sources. These detectors can be fabricated on CMOS foundry wafers resulting in large format focal planes greater than 1000×1000 and pixel sizes only limited by photolithographic technologies. The increase in temperature coefficient of resistance claimed within results in IR detectors capable of NEDT of less than 10 mK at low cost.