Photocathode
An electron-emitting photocathode includes a base and a large number of projecting elements such as microscopic wires projecting from a surface of the base. The photocathode has high quantum efficiency, and hence can be used as the emitting element in a sensitive phototube.
1. A method of making a photocathode comprising:
(a) providing a template having a plurality of pores, each of said pores having an open end;
(b) depositing material in said pores to form elements;
(c) providing a base for electrically connecting said elements; and
(d) after said depositing step, removing at least a portion of said template to expose the elements.
2. A method as claimed in claim 1 further comprising the step of coating said exposed elements with a low work function material.
3. A method as claimed in claim 1 wherein said step of providing a template includes anodizing aluminum to form said template.
4. A method as claimed in claim 1 wherein said step of providing a base includes depositing material in said pores until said pores overflow and forms said base as a layer which connects said elements to one another.
5. A method as claimed in claim 1 wherein said step of providing a base includes forming said base at least in part from a portion of said template.
6. A method as claimed in claim 5 wherein said step of exposing said elements includes chemically etching said template.