The GaAs͑113͒B surfaces were prepared by molecular-beam epitaxy and were in situ studied by low-energy electron diffraction and scanning tunnelling microscopy. We present results for two different surface structures, the recently observed ͑8ϫ1͒ reconstruction and an As-rich structure. For the ͑8ϫ1͒ reconstruction we confirm a model that consists of Ga dimer zigzag chains along ͓332͔ in two atomic levels. We report on the reflection high-energy electron diffraction ͑RHEED͒ during growth. RHEED

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... cillations are observed mainly with the electron beam along ͓110͔ from which it is concluded that growth occurs through two-dimensional nucleation and propagates along ͓332͔. The As-rich structure represents a remarkable case intermediate between a stable singular and an unstable facetted surface: Locally, As adatoms and dimers create a 1ϫ and a 2ϫ periodicity but long-range order does not exist; nevertheless, the surface comprises large terraces that are separated by welldeveloped steps.