In this paper, a series of in situ nanofabrication techniques of nanostructures, including cutting, bending and welding of carbon nanotubes (CNTs), inside a field emission scanning electron microscope (FE-SEM) is reported. In the CNT cutting technique, a CNT was exposed to a low energy beam assisted with 1 seem oxygen gas flow. The proposed technique is effective being capable of cutting a CNT in less than 1 minute. It was found that, although the total pressure of specimen chamber reached 10-2Pa, high speed cutting occurs only in the area close to the nozzle. The presence of oxygen gas in the vicinity of the CNT can be applied also for the bending of CNT, if some conditions of the cutting technique are changed. These include the increase of the acceleration voltage and/or setting the oxygen gas nozzle farther from the sample, and/or reducing the irradiation time. Using the proposed bending method the angles larger than 90deg can be formed and the location of the kink can be set accurately. It is also shown, that tungsten can be deposited on a substrate by the electron-beam-induced deposition (EBID), if the oxygen of the proposed cutting technique is replaced by W(CO)6. In this paper, these three nanofabrication methods were exploited in creation of a two dimensional (2D) nanostructure, the letters N and U, and a three dimensional (3D) nanostructure, the letter N. The 2D letters were constructed from 6 CNTs assembled on a substrate while the 3D letter N was bended from a single CNT and fixed to stand on a substrate. Based on the high performance of the proposed techniques, it is suggested that the cutting, bending, and welding techniques inside SEM will become widely utilized in the fabrication and assembly of nanodevices and in the characterization of nanomaterials.

We report a single tungsten nanowire successfully grown by controlling the distance between the emitter and substrates with a robotic nanomanipulator moved at a speed of 15 nm/s. When we draw the emitter far from the substrates during electron emission, the longest nanowire at the tip can grow continually, because the electron field at the tip is stronger than the other parts of nanowires. Although multiple nanowires grow at the beginning, the result is that only one nanowire can grow continually at the tip of carbon nanotubes (CNTs). We also show tree-like nanowires on the tip of a CNT without inter-electrode control. These nanowires were induced by field emission, with tungsten hexacarbonyl as precursors. The nanowire's geometric properties were characterized with transmission electron microscopy (TEM) and its composition was detected with TEM energy dispersive X-ray spectrometry (EDS). The EDS spectrum showed that the nanowires are mainly made of tungsten and carbon. The degradation of CNT emitter is an important problem and influences the device's stability and lifetime. We propose that the growth of nanowires can be used for modifying degraded emitters

Field emission properties of individual multi-walled carbon nanotubes (MWNT) have been investigated and applied to several nano devices. Field emission current changes with the distance between the tip of a carbon nanotube (CNT) emitter and a counterpart anode, which can be applied as the principle for an approaching sensor to detect nanometer scale distance by the observation of field emission current in real time. Higher field emission current in microampere-scale from a CNT emitter has been shown strong enough for performing electron-beam-induced deposition (EBID) without obvious degradation of emitters. EBID with CNT emitters can provide much higher specific deposition rate, potentially better productivity due to the possibility to be used in parallel, and richer metallic composition as introducing organometallic precursors such as W(CO)/sub 6/ as presented In this work. Energy dispersive X-ray spectrometry (EDS) analysis on deposits from W(CO)/sub 6/ shows that the mass of tungsten reaches up to over 80% among the compositions.

A nano laboratory-a prototype nano manufacturing system-is presented, which is composed with a nanorobotic manipulation system with 4 units and 16 degrees-of-freedom (DOFs), a nano fabrication system based on electron-beam-induced deposition (EBID) with an internal or external precursor evaporation reservoir equipped with a thermal field emission electron source or a nanotube cold cathode, and a real-time observation and measurement system based on a field emission scanning electron microscope (FESEM) equipped with 3-4 conventional atomic force microscope (AFM) cantilevers, piezoresistive levers or nanotube probes. Nanotube devices including a mass flow sensor, a linear bearing, and nanotube scissors are fabricated in the nano laboratory.