| 摘要 |
1418002 Cathode materials MULLARD Ltd 21 Aug 1973 [24 Nov 1972] 54387/72 Heading H1D A photocathode 3 comprises an epitaxial layer 4 of photocathode material on a single crystal layer 5 of GaInP having relative proportions of Ga and In such that the layers have the same lattice parameter; the thickness of the first layer being of the order of the diffusion length of electrons therein. The layer 4 is of GaAs doped with Zn and is activated with Cs and O. Layers 5, 4 are grown successively on a thick single crystal plate of GaAs by liquid or vapour phase epitaxy and the centre of the plate etched to leave a circular frame 6. The material of members 4, 6 may be GaInAs or InAsP. The photocathode is used in an image intensifier including an infra-red transmissive window 2 and a luminescent layer 7 on a conductive support.
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