Room-temperature discrete-charge-fluctuation dynamics of a single molecule adsorbed on a carbon nanotube

Abstract

Detection and use of physical noise fluctuations in a signal provides significant advantages in the development of bio- and neuro-sensing and functional mimicking devices. Low-dimensional carbon nanomaterials are a good candidate for use in noise generation due to the high surface sensitivity of these materials, which may themselves serve as the main building blocks of these devices. Here, we demonstrate that the addition of a molecule with high redox activity to a carbon nanotube (CNT) field-effect transistor provides tunable current fluctuation noise. A unique charge-trap state in the vicinity of the CNT surface due to the presence of the single molecule is the origin of the noise, which generates a prominent and unique slow discrete random telegraph signal in the device current. The power spectral density reveals the peculiar frequency limit of the fluctuation for different types of molecules depending on their redox activity and adsorption configuration. These results indicate that the detected noise will provide new opportunities to obtain electronic information for a single molecule combined with a nanotube surface, and that controllability of the noise may contribute to the expansion of noise utilization in future bio-inspired devices.

Performance of reservoir computing in a random network of single-walled carbon nanotubes complexed with polyoxometalate

“…In a previous work, we reported the generation of a spike signal from a device composed of a random and extremely dense network of single-walled carbon nanotubes (SWNTs) complexed with polyoxometalate (POM) [14]. It is known that the POM molecule displays a remarkable redox activity [15], which has been utilized as the source of fluctuations of electrical noise in molecular devices [16,17]. In addition to utilizing the stochastic fluctuation of the redox state, we proposed an abstract model of the network by assuming a two-dimensional (2D) structure of molecular junctions for the spike signal.…”

Current timer switch in a GaAs-based nanowire coupled with polyoxometalate nanoparticle and conductive AFM tip

“…On the other hand, it was unclear what mechanism determined the timing of the current switch. The switching timing of several ten seconds could not be explained by the time constant of the active redox of the POM NPs 21,37) .…”

In-materio computing in random networks of carbon nanotubes complexed with chemically dynamic molecules: a review

“…One approach for obtaining electrical nonlinearity Point contact current imaging atomic force microscopy (AFM) was used to measure the I-V curves, which showed nonlinear electrical properties as a result of the NPs behaving as nanodiodes on the single-wall nanotube (SWNT) wiring [17]. Another report suggested that a porphyrin single molecule can operate as a point local gate for individual SWNT FETs owing to the redox of a single molecule [18], which can be a source of telegraph noise of the system.…”