Scanning tunnelling microscopy, reflectance difference spectroscopy, low-energy electron diffraction, and photoemission studies have been performed on metal organic chemical-vapour-deposition (MOCVD)-prepared, As-terminated Si(I 0 0) surfaces. Various preparation procedures in two different MOCVD reactors at the HMI1 and NREL2 were applied and benchmarked in UHV employing two different MOCVD to ultra-high-vacuum (UHV) transfer systems. Clean arsenic-terminated Si(100) was prepared with tertiarybutylarsine (TBAs) and AsH3 as precursors at preparation temperatures of around 900 degrees C. Non-bulk-like atomic structures were observed, which have been established already by McMahon et al. [Phys. Rev. B 74 (2006) 033304; S.B. Zhang, W.E. McMahon, J.M. Olson, Su-Huai Wie, Phys. Rev. Lett. 87 (2001) 166401] before and which do not appear on Si(100) surfaces treated with pure arsenic. In-situ RDS signals showed the same fingerprint as single domain (2 x 1)-reconstructed surfaces obtained in UHV via MBE by Kipp et al. [Phys. Rev. Lett. 76 (1996) 2810], although low-energy electron diffraction (LEED) images displayed a (2 x 1)/(1 x 2) two domain surface. Temperature-resolved reflectance difference (RD) spectra did not show any energetic shift of the RDS peaks. Thus, the origin of the RD spectra appears to be different from the attribution made by Kipp et al. in their theoretical calculations. (c) 2006 Elsevier B.V. All rights reserved.