Single walled carbon nanotubes (SWCNTs) have gained interest in the field of nanoscaleconfinement of the fluids, with a variety of unexpected phenomena such as spontaneous filing,frictionless mas transport, unusual phase diagram, etc. (1). The majority of these phenomenaremains unexplored and requires experimental confirmation. In addition, the field requiresa sensitive method to carry out measurement in the level of individual and SWCNT, as theconfinement is sensitive to the tube diameter. On the other hand, the intrinsic and extrinsicelectronic properties of the SWCNT is shown to be sensitive to the diameter, defects, doping,adsorbates, and environment via SWCNT field effect transistors (SWCNT-FET) (2,3).In this contribution, we show that the electronic response of the individual SWCNT based fieldeffect transistor is an essential tool to study water-CNT coupling mechanism and accuratelyidentify the impact of water confined inside the nanotube. We investigate the charge transfercharacteristics of the SWCNT-FET, while exposing several individual SWCNT first unopened,then opened to different environment, such as ambient air, air humidity, vacuum and currentannealing under vacuum. We demonstrate that it is possible to assign CNT doping as the mainmechanism behind water-CNT coupling, and distinguish between water adsorbed outside ofthe nanotube from confined inside. Precisely, we found that putting the device under secondaryvacuum, after exposing to air humidity, shift the gate voltage neutrality point of opened SWCNTtowards more negative values, however, the secondary vacuum has no effect on the same SWCNTwhen it was closed. We also demonstrate that this behavior is independent CNT metallicity,assuming that the nanotube’s surface has been pre-cleaned using current annealing. We willalso discuss the water adsorption and desorption kinetics and dynamics.Our findings open up the possibility of using CNTFET to address long-standing issues in thenanofluidic community regarding the behavior of water confinement at the nanoscale, and alsoto use them for reliable, sensitive, and selective chemical and biological sensors.

Despite 15 years of extensive investigation, the fabrication and study of nanofluidic devices that incorporate a single carbon nanotube (CNT) still represents a remarkable experimental challenge. In this study, we present the fabrication of nanofluidic devices that integrate an individual single-walled CNT (SWCNT), showcasing a notable reduction in noise by 1 -3 orders of magnitude compared to conventional devices. This achievement was made possible by employing high dielectric constant materials for both the substrate and the CNT-covering layer. Furthermore, we provide a detailed account of the crucial factors contributing to the successful fabrication of SWCNT-based nanofluidic devices that are reliably leak-free, plug-free, and long-lived. Key considerations include the quality of the substrate-layer interface, the nanotube opening, and the effective removal of photoresist residues and trapped microbubbles. We demonstrate that these devices, characterized by a high signal-tonoise ratio, enable spectral noise analysis of ionic transport through an individual SWCNT, thus showing that SWCNTs obey Hooge's law in 1/ f at low frequencies. Beyond advancing our fundamental understanding of ion transport in SWCNTs, these ultralow-noise measurements open avenues for leveraging SWCNTs in nanopore sensing applications for single-molecule detection, offering high sensitivity and identification capabilities.