Abstract

The electron affinity of the polycrystalline chemical vapor deposited diamond surfaces was investigated using ultraviolet lights. The specimen surfaces were treated with annealing at 773K in the O₂ atmosphere and oxygen adsorbed on the specimen surface. The electron affinity of specimen surface shows positive. However, after the white light irradiate to specimen, the shift of threshold of photoyield was occurred, and the electron affinity became negative. The partial pressures of CO and O in the vacuum chamber increases with ultraviolet light irradiation. It is considered that oxygen were desorbed from specimen surface.