Effect of few-walled carbon nanotube crystallinity on electron field emission property

Abstract

We discuss the influence of few-walled carbon nanotubes (FWCNTs) treated with nitric acid and/or sulfuric acid on field emission characteristics. FWCNTs/tetraethyl orthosilicate (TEOS) thin film field emitters were fabricated by a spray method using FWCNTs/TEOS sol one-component solution onto indium tin oxide (ITO) glass. After thermal curing, they were found tightly adhered to the ITO glass, and after an activation process by a taping method, numerous FWCNTs were aligned preferentially in the vertical direction. Pristine FWCNT/ TEOS-based field emitters revealed higher current density, lower turn-on field, and a higher field enhancement factor than the oxidized FWCNTs-based field emitters. However, the unstable dispersion of pristine FWCNT in TEOS/N,N-dimethylformamide solution was not applicable to the field emitter fabrication using a spray method. Although the field emitter of nitric acid-treated FWCNT showed slightly lower field emission characteristics, this could be improved by the introduction of metal nanoparticles or resistive layer coating. Thus, we can conclude that our spray method using nitric acid-treated FWCNT could be useful for fabricating a field emitter and offers several advantages compared to previously reported techniques such as chemical vapor deposition and screen printing.

Synthesis of thin-multiwalled carbon nanotubes by Fe-Mo/MgO catalyst using sol-gel method

“…7c and e). In addition, it is very difficult to determine bundle morphology for the t-MWCNTs produced by the SG-2 catalyst; this is different from the case in previous reports, and indicates the mixture of isolated tubes and bundles of tubes [1,4]. This may be attributed to the formation of slightly larger diameter t-MWCNTs on the catalyst particles, which introduce a weak van der Waals interaction between the tubes.…”

“…Recent experimental results showed that the t-MWCNTs have good electrical and mechanical properties, and excellent electron field emission properties [1][2][3]. These characteristics make them one of the most promising candidates for bulk applications such as CNT-polymer composites, CNT film, and CNT field emission.…”

“…These characteristics make them one of the most promising candidates for bulk applications such as CNT-polymer composites, CNT film, and CNT field emission. There has been a recent flurry of interest by several researchers to synthesize tMWCNTs by catalytic chemical vapor deposition (CCVD) [1,[4][5][6]. In the previous catalyst fabrication methods for t-MWCNT synthesis, a combustion process has commonly been used to obtain Fe-Mo/MgO, [1,4] Ni-Mo/MgO [5] or Co-Mo/MgO [6] catalyst materials.…”

“…There has been a recent flurry of interest by several researchers to synthesize tMWCNTs by catalytic chemical vapor deposition (CCVD) [1,[4][5][6]. In the previous catalyst fabrication methods for t-MWCNT synthesis, a combustion process has commonly been used to obtain Fe-Mo/MgO, [1,4] Ni-Mo/MgO [5] or Co-Mo/MgO [6] catalyst materials. To prepare a homogeneous and efficient catalyst, it is desirable to fabricate well dispersed catalyst nanoparticles without agglomeration on the support materials [7][8][9].…”