The morphology of high-index GaAs surfaces

In this contribution, an overview of the research work in our group on the GaAs 112., 113.and 114.surfaces is presented. Samples were prepared by molecular beam epitaxy MBE.and analyzed in situ by low-energy electron diffraction LEED., core level spectroscopy and scanning tunneling microscopy STM.. The GaAs 112.A surface is unstable and decomposes into five facets of the orientations 1104, 111. and 1244. Real space images reveal that the facets form depressions whose horizontal cross-section is an irregular pentagon. For the GaAs 113.A surface, our results support the 8=1.reconstruction proposed by Wassermeier et al. On the GaAs 114.A surface a c 2=2.reconstruction was found. A structure model based on the GaAs 001.- 2=4.a reconstruction is in agreement with all our results. q2000 Elsevier Science B.V. All rights reserved