High-density large-scale field emitter arrays for X-ray free electron laser cathodes

High brightness electron sources are of great importance for the operation of the hard X-ray free electron lasers. Field emission cathodes based on the double-gate metallic field emitter arrays (FEAs) can potentially offer higher brightness than the currently used ones.We report on the successful application of electron beam lithography for fabrication of the large-scale single-gate as well as double-gate FEAs. We demonstrate operational high-density single-gate FEAs with sub-micron pitch and total number of tips up to 106 as well as large-scale double-gate FEAs with large collimation gate apertures. The details of design, fabrication procedure and successful measurements of the emission current from the single- and double-gate cathodes are presented.

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► Large-scale all-metal field emitter arrays (FEAs) fabricated by e-beam lithography.
► Up to 1 million tips per array of approx. 2 mm diameter.
► Demonstration of functional single-gate FEAs with sub-micron tip distances.
► Successful collimation of electrons by double-gate FEAs.