Structural Investigation Of The Znse(001)-C(2x2) Surface

Zinc selenide is a model system for II-VI compound semiconductors. The geometric structure of the clean (001)-c(2x2) surface has recently been the subject of intense debate. We report here a surface x-ray-diffraction study on the ZnSe(001)-c(2x2) surface performed under ultrahigh vacuum using synchrotron radiation which reveals the precise atomic geometry. The results are in excellent agreement with the Zn-vacancy model proposed earlier on the basis of density-functional theory calculations and unequivocally establish the correct equilibrium surface structure.