GaAsSb was grown lattice matched on InP(1 0 0) by metalorganic vapor-phase epitaxy (MOVPE). The surfaces of the samples were observed in the MOVPE reactor with reflectance anisotropy (RA) spectroscopy during and after growth. RA spectra taken during growth were similar to RA spectra of surfaces stabilized with TESb. However, the RA spectrum changed significantly and led to an As-rich surface with a higher degree of atomic order while supplying only TBAs. As- and Sb-rich GaAsSb surfaces were transferred into ultrahigh vacuum without any contamination and subsequently characterized with low-energy electron diffraction. There was great similarity of the different group-V-rich surface reconstructions of GaAsSb to the reconstructions known from their related binary compounds: As-rich GaAS(0.51)Sb(0.49) showed a clear c(4 x 4) reconstruction well known from GaAs(1 0 0), whereas Sb-rich GaAS(0.51)Sb(0.49) showed a (1 x 3) reconstruction, which was observed on GaSb(1 0 0) surfaces. (C) 2004 Published by Elsevier B.V.