In this paper, the InGa-terminated InGaAs(1 0 0) (4 x 2)/c(8 x 2) surface was studied in detail, which turned out to be the most suitable to develop an InGaAs/GaAsSb interface that is as sharp as possible. In ultra high vacuum the InGaAs surface was investigated with low-energy electron diffraction, scanning tunneling microscopy and UV photoelectron spectroscopy employing synchrotron radiation as light source. Scanning the Gamma-Delta-X direction by varying the photon energy between 8.5 eV and 50 eV, two surface states in the photoelectron spectra were observed in addition to the valence band peaks. (c) 2008 Elsevier B.V. All rights reserved.