ELECTRON SOURCE

摘要

Provided is an electron source of high efficiency and continuous high output, which operates at the room temperature while applying an exciter and which can operate in a low vacuum without needing any high voltage. The electron source is an indirect transition type semiconductor, which is made of a semiconductor material having a high bound energy as the exciter. The electron source includes an active layer (5) made of an indirect transition type semiconductor, and electrodes (8) for injecting an electric current into the active layer (5). The free exciter production efficiency is 10 % or more. The free exciter is changed into free electrons on a negative electronic affinity surface (7) formed on the active layer (5) or the active region, and the free electrons are continuously emitted.