Enhanced field emission properties of carbon nanotube films using densification technique

• Published in: Applied surface science 2019-05, Vol.477, p.211-219
• Main Authors: Lim, Yu Dian, Kong, Qinyu, Wang, Shaomeng, Tan, Chong Wei, Tay, Beng Kang, Aditya, Sheel
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Densification; Field emission; Screening effect
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.11.005

[Display omitted] •Ethanol-densification is proposed to enhance the FE properties of CNT films.•The FE current density of CNT films improved by 2–4 times after densification.•FE current density up to 10mA/cm2 is achieved by densified CNT films. It has been reported that Carbon Nanotubes (CNTs) films show much lower Field Emission (FE) current density than single CNT, due to the screening effect between CNTs. To minimize the screening effect, a widely-reported technique is to grow CNTs in isolated islands to form CNT arrays, which requires precise photolithography technique and CNT growth control. In this study, we demonstrate a simpler alternative to reduce the screening effect in CNT films using ethanol-densification. To perform densification, ethanol is dripped onto CNT films and dried in ambient condition to form CNT clusters. Densified CNT films show 2–4 times improvement in FE current density. This improvement in current density can be attributed to the enhanced localized electric field on CNT tips, as suggested by the simulation results. From the repeated densification and FE measurements, it is found that densified CNT films achieved consistent current density of 9∼11mA/cm2. At the same time, densified CNT film exhibits good FE current stability over prolonged continuous emission, with slight degradation from ∼10 to ∼9.64mA/cm2 over 4000s continuous emission.