Effect of ultraviolet light on 1/f noise in carbon nanotube networks

Noise defines the minimum level of the operational signal and is an important figure of merit for various devices. Here, we studied the low-frequency (1/f) noise characteristics of randomly oriented networks of carbon nanotubes and examined the effect of ultraviolet (UV) light on it. The amplitude of 1/f noise in our devices was strongly affected by the quality of nanotubes. This makes noise spectroscopy an effective tool to characterize the structural quality of carbon nanotube devices. UV illumination increased the device resistance and noise amplitude preserving the spectra shapes. This effect remained for tens of minutes even after the UV light was turned off. We observed a completely different trend of noise spectra and resistance with temperature as compared to UV illumination. These results indicated at least two important components of resistance that contribute to the total resistance of the device and are essential to describe the nanotube networks correctly.