FIELD-ASSISTED SEMICONDUCTOR PHOTOCATHODES FOR STREAK TUBES

Field-assisted semiconductor photocathodes (pCs) based on In0.53Ga0.47As/InP heterostructures with a Schottky barrier for the spectral range of 1.0 to 1.7 µm are investigated. A technique is presented for manufacturing PCs. The method for ultrahigh vacuum transfer of the PC into vacuum devices is discussed. It is shown that the sensitivity of a PC in a sealed-out device at ? = 1.55 µm is two to three orders of magnitude higher compared to traditional Ag-Cs-O PCs, and approaches 400 µA/W at ? = 1.6 µm for PCs with Schottky barriers of Au film. It is shown that PCs with Schottky Au barriers can be activated with Cs only and without O, and the stability is considerably better than with a Ag barrier. A strong decrease of the internal photoeffect is discovered in the case when the PC is illuminated from the metallic film side. The developed PCs can be used for time analyzing tubes to record picosecond pulses with milliwatt peak intensity.