Cold atmospheric pressure plasma jet prepares TiO2 coating on carbon fibre for field emission and explosive electron emission

Abstract

As the ‘heart’ of high-current vacuum electronic devices, explosive emission cathodes play an important role in their applications. In this work, a titanium dioxide (TiO2)/carbon fibre cathode prepared by a cold atmospheric plasma jet is reported. TiO2 on the carbon fibre surface prepared by an atmospheric plasma jet is at the mixture of anatase and rutile phases. The field enhancement factor of the TiO2/carbon fibre cathode is 6681, which is over ten times higher than that of the carbon fibre cathode. Furthermore, the TiO2 coating slows the diode impedance collapse and decreases the cathode plasma expansion velocity from 1.5–2.0 to 1.0–1.5 cm µs−1, which is explained by a cathode plasma model. The surface of the TiO2/carbon fibre cathode is covered by 1.6 cm2 plasma, far exceeding that of the carbon fibre cathode (1.1 cm2), which enables uniform explosive electron emission. The obtained results show that TiO2/carbon fibre cathodes prepared by cold atmospheric plasma jets will be potential candidates as high-current explosive electron emitters.