Study the electron field emission properties of plasma-based reduction of graphene oxide (GO): An ex-situ plasma approach

Vacuum-based electron emission devices requires fast and low turn-on field processes. Graphene oxide (GO) can be a perfect candidate for field electron emission applications. In this work, we have prepared graphene oxide (GO) via modified Hummer's method and treated it with dense plasma of argon gas (Ar). The surface morphology of the prepared GO reveals the growth of the stacked-layer and large surface area flakes of GO. Raman spectra reveals the high defective growth of GO. The impurities in the GO are due to the incorporation of oxygen moieties. For enhancing the field emission properties, the GO thin films were treated with a dense plasma of Ar gas at 50, 100, 150 and 200 W. Raman spectra strongly indicates the removal of oxygen moieties and formation of defects and vacancies in the sheet of plasma-treated GO. The field emission properties drastically improved in the scenario of plasma-treated GO field emitters. The turn-on and threshold fields were reduced after plasma treatment in comparison with pristine GO field emitters. The reduction in the turn-on and threshold fields is due to the enhancement in the edge effects, protrusion formation and modification in structural properties. The emission current density was drastically enhanced in the 200 W plasma-treated GO field emitters. The emission stability test was performed for a 600 min at 3V/μm applied electric field. The stability was enhanced with plasma power and shows the minimum current fluctuation. The field enhancement factor also improved after plasma treatment and for 200 W treated β becomes 3 times the pristine GO. We have also implemented the orthodox emission hypothesis test, which was qualified by the prepared pristine and plasma-treated GO field emitters due to the f^extr values belonging in the acceptable range. Conclusively, Ar gas plasma-treated GO field emitters can be useful for emission applications in vacuum devices.