Photoelectron properties and enhanced field electron emission of cobalt ferrite-reduced graphene oxide nanocomposite

In the present report, field electron emission (FE) characteristics of cobalt ferrite (CF) nanoparticles (NPs) decorated on reduced graphene oxide (rGO) are studied. The rGO-CF nanocomposite was synthesized by simple glycol-based route. The formation of rGO-CF nanocomposite was confirmed using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). TEM results indicated the uniform decoration of CF NPs on the rGO sheet. The average particle size of decorated CF NPs is ∼8 nm. XPS results revealed the partial reduction of GO to rGO. The ultraviolet photoelectron spectroscopy (UPS) was utilized to calculate the work function of the nanocomposite and it was found to be ∼4.3 eV. The FE properties of rGO-CF nanocomposite were investigated in planer diode assembly. The nanocomposite showed excellent FE performance with low turn-on ∼ 1.34 V/μm and threshold field ∼ 1.72 V/μm values. The maximum current density was found to be 2.8 mA/cm2, at an applied field of 2.88 V/μm. This enhancement in FE characteristics was explained on the basis of surface morphology, increased number of emitting sites, high field enhancement factor, and reduction in the work function of the emitter. The FE results suggest that rGO-CF based emitters have the potential for the development of various micro-nano electronic devices.