Geometric and electronic structure of molecular beam epitaxy-prepared GaAs (112) and (113) surfaces

Abstract

The surface structure and the electronic properties of the high-index molecular beam epitaxy (MBE)-prepared GaAs surfaces (112)A and B as well as (113)A and B were investigated in situ by low-energy electron diffraction and surface core level spectroscopy. Under MBE conditions, both (112) surfaces are unstable. The (112)A surface consists of five kinds of facets with the orientations {110}, {124} and (111). The ( 1 1 2 ) B surface forms four types of facets with the orientations ( 1 1 1 ), ( 1 1 3 ) and { 1 1 0 }. The surface core-level shift analysis on GaAs(112)A yields surface components for the As 3d peak (− 0.31 eV) as well as for the Ga 3d peak (+ 0.28 eV). On GaAs(113)A both the (8 × 1) superstructure and the core-level analysis support a structure model proposed recently by Wassermeier et al. (Phys. Rev. B, 57. (1995) 14721). After MBE preparation, the ( 1 1 3 )B surface forms facets with the orientations ( 1 1 0) and ( 1 1 1).