Epitaxial Graphene Microstructures as Electron Emission Sources Towards Emission of Soft X-rays

Electron emission sources are of critical importance in imaging applications, most especially in electron microscopy and X-ray generation. Graphene nanostructures, crafted by CVD, arc discharge, or exfoliation, have been shown to exhibit electron emission under bias, with theoretical outputs exceeding thermionic or field emission sources of similar dimensionality and applied bias conditions. With even low applied bias (3 - 5 V) nanoribbons suspended in high vacuum exhibited phonon-assisted electron emission, resulting in nA emission currents at internal electric fields and external pulling voltages both nearly 100x less than comparable thermionic or field emission sources. Simulations for epitaxial graphene microstructures have shown the potential for emission sources over 10000x larger, with emission currents as high as mA at comparable pulling voltages. Fabrication is easily accomplished with minimal contact photolithography steps and plasma etching, ensuring the preservation of the graphene surface and allowing for device control mechanisms that are simpler and more robust than those presented in referenced works. Presented here is a treatment of the preparation, fabrication, and testing of these epitaxial graphene microstructure electron emission arrays.