X-ray diffraction studies of the InSb(001) surface

The (001) surface of the III-V alloy semiconductors exhibits many reconstru ctions with large unit meshes. The appearance of a given reconstruction dep ends on the processing conditions and, in particular on the stoichiometry a t the surface. A surface X-ray diffraction study of the atomic structure of the Sb-rich c(4x4) and the In-rich c(8x2) surfaces is described which allo ws for the first time, a detailed atomic model of these important reconstru ctions to be derived. The basic units consist of groups of Sb dimers and ro ws of In atoms on top of an Sb terminated bulk. The local bonding is simila r to that found in rhombahedral Sb and tetragonal In bulk structures. The r esults explain why the Sb rich surface is used as a starting point for the growth and are relevant to other III-V (001) surfaces.