Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is reali...

Vertically, carbon nanotube (CNT) arrays were successfully fabricated on hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition using gas mixtures of acetylene (C2H2) and hydrogen (H2) with Fe/Al2O3 catalysts. The CNTs were found to be graphitized with multi-walled structures. Different H2/C2H2 gas flow rate ratio was used to investigate the effect on ...

Selective area growth of carbon nanotubes (CNT) has been used to control the diameter of CNTs. Narrow lines of SiO2 (12−60 nm) are formed at the cleaved face of a Si/SiO2/Si multilayer structure. CNTs are then grown by a chemical vapor deposition process with a ferrocene/xylene/ H2/Ar mixture at 700 °C. CNTs are observed to grow only on the exposed SiO2 surface at the edge of the “mesa” structu...

The surfaces of acid- and amine-functionalized carbon nanotubes (C-CNT and N-CNT) were decorated with MnO2 nanoflakes as supercapacitors by a spontaneous redox reaction. C-CNT was found to have a lower edge plane structure and fewer defect sites than N-CNT. MnO2/C-CNT with a highly developed surface area exhibited favorable electrochemical performance. To determine the atomic/electronic structu...

Carbon nanotubes (CNT) possess excellent mechanical properties to play the role as reinforcement for imparting strength and toughness to brittle hydroxyapatite (HA) bioceramic coating. However, lack of processing technique to uniformly distribute multiwalled CNTs in HA coating and limited studies and sparse knowledge evincing toxicity of CNTs has kept researchers in dispute for long. In the cur...

We present a continuous manufacturing process for low-cost and scalable production of vertically aligned carbon nanotube (CNT) forests, along with continuous rolling of the CNTs to create horizontally aligned (HA) CNT ribbons and sheets. These methods are capable of producing uniform films over waferscale dimensions and beyond, and the CNTs can be patterned by lithography and plasma etching to ...

A parametric study of carbon nanotube (CNT) synthesis from catalytically active porous anodic Al–Fe–Al multilayer templates was conducted with respect to pore aspect ratio, Fe layer thickness, CNT synthesis temperature, and pre-anodization thermal annealing. Performance metrics included CNT catalytic activity and the pore wall integrity at the Al–Fe–Al interface. The observed CNT density was a ...

Feedstock diffusion and decomposition in the root growth of aligned carbon nanotube (CNT) arrays is discussed. A nondimensional modulus is proposed to differentiate catalystpoisoning controlled growth deceleration from one which is diffusion controlled. It is found that, at current stage, aligned multi-walled carbon nanotube (MWNT) arrays are usually free of feedstock diffusion resistance. Howe...

This work examines the recent developments in non-traditional catalyst-assisted chemical vapour deposition of carbon nanotubes (CNTs) with a view to determining the essential role of the catalyst in nanotube growth. A brief overview of the techniques reliant on the structural reorganization of carbon to form CNTs is provided. Additionally, CNT synthesis methods based upon ceramic, noble metal, ...

Commercialization of materials utilizing patterned carbon nanotube (CNT) forests, such as hierarchical composite structures, dry adhesives, and contact probe arrays, will require catalyst patterning techniques that do not rely on cleanroom photolithography. We demonstrate the large scale patterning of CNT growth catalyst via adaptation of a laser-based electrostatic printing process that uses m...