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Highly efficient electron emission of 48.5% was demonstrated by a graphene/oxide/semiconductor (GOS) structure. The main factors contributing to this performance were investigated by analyzing the ...

A graphene-oxide-semiconductor (GOS) planar-type electron source was fabricated by direct synthesis of graphene on an oxide layer via low-pressure chemical vapor deposition. It achieved a maximum electron emission efficiency of 32.1% by suppressing the electron inelastic scattering within the topmost gate electrode using a graphene electrode. In addition, an electron emission current density of 100 mA/cm^2 was observed at an electron emission efficiency of 16.2%. The electron energy spread was well fitted to Maxwell-Boltzmann distribution, which indicates that the emitted electrons are the thermally equilibrium state within the electron source. The full-width at half-maximum energy spread of the emitted electrons was approximately 1.1 eV. The electron emission efficiency did not deteriorate after more than 42 h of direct current operation. Thus, the GOS planar-type electron source has the potential to be an excellent electron gun for electron microscopy., This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in (https://aip.scitation.org/doi/10.1063/1.5091585) and may be found at [https://doi.org/10.1063/1.5091585].

We have proposed and developed a relatively low costed and simple constructed scanning electron microscope only with single objective lens but other convergent electron optics like condenser lenses using graphene-oxide-silicon planar type cold cathode (GOS) as an electron source. GOS has many superior aspects such as low voltage and low vacuum operation, stable emission, high emission current density, high efficiency against diode current, and so on. Especially, the quite low divergence of emitted electron beam from GOS have been expected to realize ideal parallel beam.

The planar type electron emission devices based on a graphene-oxide-semiconductor (GOS) structure were developed. The GOS type electron emission devices fabricated by the combination of low temperature graphene deposition process of 800 $^{\circ\mathrm{C}}$ and the post device annealing at 300 $^{\circ\mathrm{C}}$ in vacuum achieved both of very high electron emission efficiency more than 10 % and high electron emission densities of around 100 mA/cm$^{\mathbf{2}}$