NEGATIVE EFFECTIVE-ELECTRONIAFFINITY SILICON ELECTRON EMITTER NEGATIVE EFFECTIVE-ELECTRONIAFFINITY SILICON ELECTRON EMITTER

摘要

1414400 Cathode materials and processing RCA CORPORATION 23 May 1973 [2 June 1972] 24533/73 Heading H1D A negative effective electron affinity electron emitter is formed by heating a P-type Si body in vacuum at 1100-1420‹ C., applying a work function reducing material, reheating at a lower temperature and applying further said material. The method avoids cleaning Si by sputtering and subsequent annealing. A Si reflecting photocathode is prepared by mounting a P-type monocrystalline Si disc 14 in a discharge tube envelope from which extends an exhaust tube 22 including containers 26, 28 with material which releases Cs and O when heated. The envelope is degassed by baking and the disc heated by current through leads 21 to 1300‹ C. for 3 seconds. On cooling Cs is released until photoemission passes a maximum, then O 2 is released until photoemission reaches a maximum. The heating and sensitizing may be repeated. The cathode is heated to 1000‹ C. for 3 seconds and on cooling sensitized with Cs and O. These heating and sensitizing steps may be repeated until the desired photosensitivity is achieved. The Cs may be replaced by Rb. The method is used for secondary emissive dynodes and P-N cold cathodes.