A point field emission tungsten cathode obtained by faceting of the tungsten surface induced by ultrathin gold film: Observations by means of scanning field emission microscope (SFEM)

The paper describes a simple procedure of the preparation of a point field emission tungsten cathode for applications to ultra high vacuum devices. Scanning field emission microscope (SFEM) was used as the testing method. The point electron source was obtained by the reconstruction of the tip caused by annealing in the presence of electric field. In order to facilitate the process of the reconstruction, an ultrathin gold film was evaporated onto the tip surface before annealing. As the result of the combined action of all these factors one obtains, so called build-up, ultra sharp tip, which is a point field emission electron source.