Variation in the Yield of Photoelectrons Emitted from (111) and (111) Surfaces of a Gallium Phosphide Crystal with the Diffraction Condition of X-Rays

Difference in the yields of electron omission from (111) and (111) planes of a polar crystal of gallium phosphide is studied under the diffraction condition of X-rays. The symmetric 111 and 111 Bragg-case diffractions are used in the double-crystal arrangement of (+, -) setting for Cu K α radiation. Profiles of the yield curve of Ga L -photoelectrons obtained for two polar planes differ markedly from each other because of the difference in the X-ray wave fields formed in the crystal.