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Low dimensional electronic materials offer a platform to observe biological processes with unprecedented spatial and temporal resolution. To probe the major sources of noise in CNT FETs, we have systematically controlled the environment surrounding a CNT. We quantify the noise generated by the substrate, surface adsorbates, and biological molecular interactions with a CNTs surface. We show that electrostatically induced disorder at the CNT interface is a significant source of parasitic noise. By removing the substrate interaction and surface adorbates we find a 19-fold reduction in the power spectrum of electronic noise.
In some cases the electrostatic perturbation generated by a single charge trap in close proximity to a CNT can dominate the noise in a CNT FET. The charge trap creates a scattering site in the CNT. When the trap is occupied, device conductance can be significantly reduced, leading to random telegraph signals (RTS), in constant-bias current. We experimentally and theoretically demonstrate that the amplitude of the RTS depends strongly on the Fermi energy and polarity of the free carriers. The high signal to noise ratio that we observe demonstrates that it is possible to detect the fields generated by the fluctuations of a single electron charge at room temperature.