Use of x-ray reflectivity for determining the Si(111)3×3-Bi surface structures

Abstract

Absolute reflectivities of x-rays from the Si(111)3×3-Bi surface were measured along the 00 and 12̄ reciprocal-lattice rods. Two phases of the surface, a low-coverage phase and a high-coverage phase, were recognized from the reflectivity measurement. The Bi coverages of the two phases were determined as 1 ML and 1/3 ML. The 1-ML phase takes the milk stool structure. For the 1/3-ML phase the adsorbed Bi atom is found to be on the T4 site and the distance between the Bi layer and the first Si layer is 1.60 . For data analysis, expressions of the absolute reflectivities obtained by a newly developed dynamical theory are used. © 1995 The American Physical Society.