Atomic Structure of Faceted Planes of InAs Quantum Dots on GaAs(001) Studied by Scanning Tunneling Microscopy

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Abstract
Three-dimensional island structure of the lattice mismatched InAs/GaAs(001) system was prepared by molecular beam epitaxy (MBE) and its images showing atomic structure on faceted planes were taken in situ by ultra-high vacuum scanning tunneling microscopy (UHV-STM). (113), (114) and (215) faceted planes are observed on 3D InAs islands. Based on high resolution STM images, atomic structural models of these faceted planes surfaces are proposed. The structure of the (113) planes is found to be different from those observed on nominal-flat InAs and GaAs (113) surfaces. The structural information will be useful for characterization of surface energy/stress of the islands, diffusion process on the surface, and interface properties. The result sheds a light on the formation mechanism and self-organization process of quantum dots.