Using different supporting mediums to improve the field emission characteristics of carbon nanotubes

• Fe/Ni, diamond, and bentonite nano-particles were used as supporting mediums to form the medium-CNTs composites.
• Addition of supporting mediums can decrease effect of gaps and decrease the resistance of CNTs films between the long CNTs.
• Addition of Fe/Ni and diamond supporting mediums enhance the field emission properties of the medium-CNTs composite films.
• The Fowler-Nordheim theorem is used to describe the behavior of a generalized field emitting system.

In this study, multi-wall CNTs synthesized by thermal chemical vapor deposition method were used to fabricate carbon nanotubes (CNTs)-film emitters by using screen-printing method. Different nano-materials, including Fe/Ni, diamond, and bentonite nano-particles with different shapes and different electrical conductivity, were used as supporting mediums to form the medium-CNT composites. Those composites were used to print the medium-CNT composite films as emitters and investigate their field emission characteristics. The enhancement effect in the field emission property of the prepared medium-CNT composite films and the theorems to cause the enhancement were investigated by differently analyzed and measured processes. Scanning electron microscope images suggested that the enhancement in the field emission properties of the medium-CNT composite films was caused by the supporting mediums having comparably matching dimensions and suitable shapes. The addition of medium materials could construct a matching structure to decrease the gap's barrier and then to increase the probability of ohmic contact between CNTs and substrates. We would show that as Fe/Ni and diamond nano-particles were used as mediums, the medium-CNT composite films would have large field emission current and have good stability and uniformity.

Fig. Luminescence of phosphor layer excited by the electron emissions from prepared films, 2.5 cm by 2.5 cm: (a) D–CNT film, (b) M–CNT film, and (c) B–CNT film.Figure optionsDownload as PowerPoint slide