III-V photocathode with nitrogen doping for increased quantum efficiency

摘要

An increase in the quantum efficiency of a III-V photocathode is achieved by doping its semiconductor material with an acceptor and nitrogen, a column-V isoelectronic element, that introduces a spatially localized energy level just below the conduction band similar to a donor level to which optical transitions can occur. This increases the absorption coefficient, &agr;, without compensation of the acceptor dopant. A layer of a suitable I-V, I-VI or I-VII compound is included as an activation layer on the electron emission side to lower the work function of the photocathode.