SURFACE QUALITY AND ATOMIC-STRUCTURE OF MBE-GROWN GAAS(100) PREPARED BY THE DESORPTION OF A PROTECTIVE ARSENIC LAYER

Scanning tunneling microscopy (STM) was used to study clean GaAs(100) surfaces prepared by thermal desorption of a protective Arsenic layer. The GaAs samples were grown by MBE using an As, cracker cell. After t ransfer through atmosphere and insertion into the UHV chamber, clean, well ordered surfaces with different reconstructions were prepared by thermal annealing. The atomic structure and the morphology of the surf aces were found to depend sensitively on the annealing procedure. For several differently reconstructed surfaces STM images with atomic reso lution were obtained similar to those recently published for in-situ-M BE investigated surfaces. These results demonstrate that the As-decapp ing technique is, in fact, a versatile tool for preparing well-defined GaAs(100) surfaces.