INVESTIGATION GROWTH OF GaN NEGATIVE ELECTRON AFFINITY PHOTO-CATHODES MATERIAL

Two to five micrometer thick P-Al_xGa_1-xN/GaN layers with 0＜X≤0.4 were grown by low-pressure metal organic chemical Vapour deposition on sapphire（0001）substrates.For Al cocentrations 0.2＜X＜0.3 in the Al_xGa_1-xN layers,The assessment of P-type GaN active layers Shows electron diffusion Lengths of 2 to 5 μm for a doping level of 1×10¹⁹/cm³ with neglectible interface recombination.Rep-roducibility of the processing.and furthest development of MOCVD for large scale growth of ultraviolet photo-cathode materials is discussed.