A comparative study of 1/f noise and temperature coefficient of resistance in multiwall and single-wall carbon nanotube bolometers

The 1/f noise and temperature coefficient of resistance (TCR) are investigated in multiwall carbon nanotube (MWCNT) film bolometers since both affect the bolometer detectivity directly. A comparison is made between the MWCNT film bolometers and their single-wall carbon nanotube (SWCNT) counterparts. The intrinsic noise level in the former has been found at least two orders of magnitude lower than that in the latter, which outweighs the moderately lower TCR absolute values in the former and results in higher bolometer detectivity in MWCNT bolometers. Interestingly, reduced noise and enhanced TCR can be obtained by improving the inter-tube coupling using thermal annealing in both SWCNT and MWCNT films, suggesting much higher detectivity may be achieved via engineering the inter-tube coupling.