CHANGES IN THE SURFACE-MORPHOLOGY OF GE(001) DUE TO SB ADSORPTION

The structure and morphology of Sb-covered Ge(001) surfaces has been s tudied with scanning tunneling microscopy and low-energy electron diff raction. After deposition of submonolayers of Sb at room temperature a nd annealing at 350 degrees C, the images show an interfacial mixing o f symmetrical Sb dimers and Ge dimers. At saturation coverage, the (2 x I) reconstruction exhibits a high density of antiphase domain bounda ries. Upon annealing at temperatures between 480 and 510 degrees C the morphology of the surface changes drastically without Sb desorption. Oriented two-dimensional islands and vacancies are formed which have d istinctive shapes. The rearrangements which occur on the surface can b e understood in terms of stress domains, which reduce the surface stre ss.