Field Emission of Multi-Walled Carbon Nanotubes from Pt-Assisted Chemical Vapor Deposition

Abstract

Multi-walled carbon nanotubes (MWNTs) were grown directly on a metal substrate with the assistance of Pt using a chemical vapor deposition method. In addition, the growth mechanism of Pt-assisted catalytic CNT was discussed. MWNTs were characterized by SEM, TEM, AFM, Raman, and EDS, and the field emission (FE) properties were investigated, comparing with the direct grown MWNTs. The results showed that CNTs could not been synthesized by Pt particles alone under the experimental condition, but Pt may accelerate the decomposition of the carbon source gas, i.e., assisting MWNT growth with other catalysts. The Pt-assisted MWNTs were longer with larger diameters of around 80 nm and possessed better structural qualities with very few catalyst particles inside. Improved field emission properties were demonstrated for the Pt-assisted MWNTs with lower turn-on fields (for 0.01 mA·cm−2 current density) of 2.0 V·μm−1 and threshold field (for 10 mA·cm−2 current density) of 3.5 V·μm−1, as well as better stability under a long-term test of 80 h (started at 3.0 mA for the Pt-assisted emitter and 3.25 mA for the direct grown emitter). This work demonstrated a promising approach to develop high performance CNT field emitters for device applications.

Effect of Crystallinity on the Field Emission Characteristics of Carbon Nanotube Grown on W-Co Bimetallic Catalyst

“…Singh prepared carbon nanotubes with the Mo-Fe bimetallic catalyst, which had a higher field enhancement factor and higher emission current density compared with the pure Fe catalyst [22]. Tang demonstrated that Pt-Ni-assisted MWNTs had lower turn-on fields of 2.0 V/µm and a threshold field of 3.5 V/µm as well as better stability [23]. However, more systematic works should be carried out to investigate the intrinsic mechanism of bimetallic catalysts impacting the CNT's growth and its field emission characteristics.…”