Study of Cold Field Emission from CNT Using Nanomanipulation Based on Nanogripper with Shape Memory Effect

Abstract

Carbon nanotubes (CNTs) are one dimensional nanomaterials with unique functional properties, including electronic, mechanical and many other properties. CNTs are very promising for different nanoelectronic devices. Among them are CNT-based nano-transistors, generators, NEMS, single photon sources, components for nanophotonics, MEMS/NEMS, nanosensorics, and many others. One of the most outstanding functional properties of CNT with many future applications is electron cold field emission. The unique field emission properties of CNTs were first observed in 1994. Since 1994 there are many publications about field emission from CNTs, but till now the mechanism of its occurrence is still not clear. In many papers CNTs are considered as the thinnest metal-conducting cathode with the highest aspect ratio, i.e. the largest electric field amplification factor. In such papers the volt-ampere characteristics (VAC) obtained from CNT is considered in frame of the Fowler-Nordheim law. But in other recent papers it was shown, that in many cases experimental results show that VAC of CNT demonstrate deviations from Fowler Nordheim's law, at least at high and low currents. So the question raises about other possible mechanisms of electron cold field emission from CNT. In this report we use bottom up mechanical nano manipulation for creating nanodevices and set ups to study the electron cold field emission from CNTs. The analysis of many works on field emission from CNTs, as well as our experiments, convincingly show that the mechanism of CNT field emission is different from the emission of metal pointed cathodes. In the present report a new model of cold field emission from CNTs is suggested taking into account the Friedel oscillations of the charge density.