Cobalt ferrite decorated multiwalled carbon nanotubes as the electrode for efficient field electron emission

Abstract

In the present study, Cobalt Ferrite (CF) nanoparticles with different weight concentrations were successfully decorated on Multi-Walled Carbon nanotubes (MWCNT) using a simple glycol assisted chemical route. The physicochemical and electronic properties of CF decorated MWCNTs (MWCNT-CF) were accomplished with the help of different techniques such as X-ray Diffraction (XRD), Raman Spectroscopy, Transmission Electron Microscopy (TEM), X-ray Photo-electron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). Further, the effect of CF concentration on Field Emission (FE) characteristics of MWCNT-CF is investigated. The FE studies revealed that, CF decorated MWCNT emitter (MWCNT-CF; 1:1) exhibits lower turn on (0.52 V/μm, at 10 μA/cm2) and threshold fields (0.62 V/μm, at 100 μA/cm2) in contrast to pristine CF, MWCNT, and MWCNT-CF (1:0.5 and 1:2). Interestingly, from the MWCNT-CF (1:1) emitter, very high emission current density ~10,408 μA/cm2 has been extracted at a relatively lower applied field of 1.18 V/μm. The enhancement in FE characteristics of MWCNT-CF emitters is attributed to lowering of work function measured from the UPS analysis and increased number of emitting sites. The results imply that very high current density field emitters can be fabricated using a simple strategy based on the decoration of MWCNT's with CF nanoparticles. © 2020 Elsevier B.V.