Growth of dense CNT on the multilayer graphene film by the microwave plasma enhanced chemical vapor deposition technique and their field emission properties

Abstract

Catalyst assisted carbon nanotubes (CNTs) were grown on multilayer graphene (MLG) on copper and silicon substrates by the microwave plasma enhanced chemical vapor deposition technique. The transmission of the MLG was found to vary between 82 to 91.8% with the increase of deposition time. Scanning electron microscopy depicted that the MLG film survived at the deposition condition of CNTs with the appearance of the damaged structure due to the plasma. Growth of CNTs was controlled by adjusting the flow rates of methane gas. The density of carbon nanotubes was observed to increase with a higher supply of methane gas. It was observed that the field emission properties were improved with the increased density of CNTs on MLG. The lowest turn-on field was found to be 1.6 V mm À1 accompanied with the highest current density of 2.8 mA cm À2 for the CNTs with the highest density. The findings suggested that the field emission properties can be tuned by changing the density of CNTs.

Ultrasensitive and Wearable Carbon Hybrid Fiber Devices as Robust Intelligent Sensors

“…A typical CNT was further investigated using a transmission electron microscope (TEM) image (Figure 1i), which showed distorted hollow carbon tubelike derivates containing nickel metal nanoparticles on the tip. Similar to the previous reports that utilized nickel metals to catalytically grow CNTs using the CVD method in acetonitrile, 39 ethylene, 40 and acetylene, 41 treatment with melamine under a high temperature can also trigger in situ growth of CNTs on active nickel metal nanoparticles. The doping of nitrogen atoms into the fiber was verified by X-ray photoelectron spectroscopy (XPS) in which nitrogen took up 11.0 at%.…”

Plastic-derived substrate-grown carbon nanotubes as freestanding electrode for hydrogen evolution in alkaline media

“…The carbon cap is then disconnected from the catalyst as a result of the internal stress accumulated, forcing the catalyst particle away, thereby creating a fresh catalytic surface for the nucleation of a new carbon segment shell (Giannakopoulou et al, 2021;Mohana Krishna et al, 2014). Another contributing factor could be the competition between surface and bulk diffusion of carbon in the catalyst particles (Bisht et al, 2015). In the case of hollow-core nanotubes, the surface diffusion predominates, forming smaller diameter CNTs as they nucleate on small catalyst particles.…”