Enhanced field emission from cerium hexaboride coated multiwalled carbon nanotube composite films: A potential material for next generation electron sources

Abstract

Intensified field emission (FE) current from temporally stable cerium hexaboride (CeB 6) coated carbon nanotubes (CNTs) on Si substrate is reported aiming to propose the new composite material as a potential candidate for future generation electron sources. The film was synthesized by a combination of chemical and physical deposition processes. A remarkable increase in maximum current density, field enhancement factor, and a reduction in turn-on field and threshold field with comparable temporal current stability are observed in CeB 6-coated CNT film when compared to pristine CeB 6 film. The elemental composition and surface morphology of the films, as examined by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray measurements, show decoration of CeB 6 nanoparticles on top and walls of CNTs. Chemical functionalization of CNTs by the incorporation of CeB 6 nanoparticles is evident by a remarkable increase in intensity of the 2D band in Raman spectrum of coated films as compared to pristine CeB 6 films. The enhanced FE properties of the CeB 6 coated CNT films are correlated to the microstructure of the films. V

Improved field emission from indium decorated multi-walled carbon nanotubes

“…The cf values for uncoated and coated films are given in the Table 1. The effective emission area (S eff ) is calculated from F-N equation for CNT tips using the following relation [40,27].…”

“…There are reports pertaining to decoration of CNTs with various low work function materials in the nanoparticle form such as Cs , LaB 6 , Hf, BaSrO, SrTiO 3 , CeB 6 , Ta etc. Also, some wide band gap materials like SiO 2 and MgO were deposited using different coating techniques like sputtering, spin coating, thermal evaporation, and pulsed laser deposition (PLD) [22][23][24][25][26][27][28][29]. Enhanced field emission from CNTs after plasma treatment [30], low energy ion bombardment [31], high temperature annealing [32], electrical treatment [33] and CNT carpet were also reported [34].…”

Enhanced field emission from lanthanum hexaboride coated multiwalled carbon nanotubes: Correlation with physical properties

“…Although the dependence of b on the surrounding environment of the emitter reveals its geometrical dependence on the h/r ratio to some extent, existing reports show its geometrical dependence proportional (with or without addition to a constant factor) to h/r. [9][10][11] Therefore, while designing a FE emitter the above aspects are to be considered with utmost care. 8,9 However, even if a field emitting material emits electrons efficiently, it does not ensure temporal stability of current under operative conditions at high electric fields for a substantially longer duration.…”

“…[9][10][11] Therefore, while designing a FE emitter the above aspects are to be considered with utmost care. 8,9 However, even if a field emitting material emits electrons efficiently, it does not ensure temporal stability of current under operative conditions at high electric fields for a substantially longer duration. Therefore, it is important to grow FE materials that also have long temporal stability so that they can be used in FE devices with enhanced reliability.…”

Highly enhanced and temporally stable field emission from MWCNTs grown on aluminum coated silicon substrate

“…23,24 The improvement in temporal stability is also indicated in CNTs with various over layers, and nanoparticle decoration, like Ru, LaB 6 , CeB 6 , SrTiO 3 etc. 21,[38][39][40] at relatively lower current densities (∼ 1 mA/cm 2 or less). All results described above can be explained qualitatively in the following manner.…”