New players for better imaging

Advanced imaging and electronic devices require the development of efficient electron sources. In the search for new cathodes capable of producing a strong electron flux with low energy consumption, carbon materials have attracted a great deal of attention. Due to their extraordinary field emission properties, control of the morphology and electron properties of nanocarbon species should open many exciting opportunities in this direction.

With EU funding of the project 'Fundamentals and applications of nano-carbon electron emitters' (FANCEE), scientists are providing new insights into the fundamental properties and application potential of nanocarbon-based materials. In particular, FANCEE is placing focus on revealing the fundamental mechanisms of thermionic and laser-assisted electron emission of these materials. Establishing a relationship between the structural and electron emission properties should enable scientists to obtain efficient and stable emission sources. This will in turn help create strong electron guns and efficient cathodoluminescent light sources.

Scientists have demonstrated that the nanometric curvature of the diamond needle apex makes it possible to design a new class of high-performance electron guns. The developed chemical vapour deposition technique has enabled the production of large-area thin-film graphene that can be employed for various optoelectronic devices.

With the help of experimental data, FANCEE has determined the field emission characteristics of nanocarbon cathodes with different morphological, composition and structural properties. Thermionic and field emission regimes and their mutual transformations have also been studied for different carbon films.

Except for thermionic emission, scientists have also studied laser-assisted field emission by irradiating graphene-based materials with ultrashort pulses. The study results were used to explain the experimental results obtained from nanographite and carbon nanotube cathodes.

Prototypes of a cathodoluminescent lamp and an X-ray tube have been successfully developed. The on-board electron gun prototype is currently used in a satellite.

FANCEE has produced many reports and organised a number of meetings and workshops to disseminate its results. The project is expected to provide fundamental new insights into the extraordinary field emission properties of nanocarbon structures.