Structural Model for the Negative Electron Affinity Surface of O/Cs/Si(001)2×1

Abstract

A wide-terrace single-domain Si(001)2×1 surface has been used to prepare a single-domain Si(001)2×1-Cs surface and a negative electron affinity (NEA) surface of single-domain O/Cs/Si(001)2×1. An X-ray photoelectron diffraction study has reinforced the reliability of a Cs double-layer model for the Si(001)2×1-Cs surface. X-ray photoelectron diffraction for the NEA surface has revealed that the Cs double-layer is preserved and adsorption of oxygen takes place in a hollow site on a level that is coplanar with the lower Cs layer.