Ž . Applied Surface Science 162–163 2000 380–383 www.elsevier.nlrlocaterapsusc ž / ž / ž / Sb-terminated Si 110 , Si 100 and Si 111 surfaces studied with high resolution core-level spectroscopy A. Cricenti a, ) , C. Ottaviani a , C. Comicioli a , C. Crotti b , L. Ferrari a , C. Quaresima a , P. Perfetti a , G. Le Lay c a Istituto di Struttura della Materia, CNR, Via Fosso del CaÕaliere 100, 00133 Rome, Italy b IMAI, CNR, Area Science Park, Trieste, Italy c CRMC2, UPR CNRS 7251, Campus de Luminy, 13288 Marseille Cedex 9, France Abstract We report on synchrotron radiation photoelectron spectroscopy studies of the Si 2p core levels obtained with very high Ž . Ž . Ž . resolution from Sb overlayers onto the low-index silicon surfaces Si 110 , Si 100 and Si 111 . The improved energy resolution of the third generation synchrotron radiation facilities has shown the presence of a strong interfacial component shifted 0.24, 0.2 and 0.13 eV, respectively, on the high binding energy side respect to the bulk peak. Such Si–Sb interface contribution is ascribed to charge transfer between the metal and the topmost silicon atoms and to the latest layers of silicon atoms distorted by the reconstruction from the ideal bulk position. A small component is always present on the high kinetic energy side and is presumably due to contribution from defects. q 2000 Elsevier Science B.V. All rights reserved. PACS: 73.20.yr; 79.60.yi; 79.60.Dp Keywords: Silicon; Semiconducting surfaces; Synchrotron photoelectron spectroscopy 1. Introduction The interaction of Sb with Si surfaces is of great interest since Sb is an important dopant material used in Si molecular beam epitaxy and is used as a w x surfactant for GerSi heterostructures 1,2 . Core- level spectroscopy was extensively used to study Ž . wx Ž . w x Sb-terminated Si 100 3 , Si 111 4,5 surfaces with some controversial results due to the limited energy resolution. For example, the 1 ML Sb-terminated Ž . wx Si 111 surface exhibits a 63 =63 reconstruction 6 composed of Sb trimers regularly residing above the ) Corresponding author. Fax: q 39-64-993-4153. Ž . E-mail address: antonio@dns.ism.rm.cnr.it A. Cricenti . w x top layer of silicon atoms on T4 sites 7–9 . Some minor contributions are observed as Sb trimers resid- wx ing on H3 sites or as different reconstructions 9 . In one core-level study of such 63 =63 reconstruction, no surface components were observed in the Si 2p wx core level 5 . Another group, by making similarities with some other surfaces, has shown in the fit proce- dure of the Si 2p spectrum, the presence of a an interfacial component shifted q0.2 eV on the high wx binding energy side respect to the bulk peak 5 . Core-level photoemission is also a sensitive probe for studying the effects of the different coordination at the surface: in fact, each core-level spectrum can be deconvoluted into components that are representa- tive of the surface and the bulk. By taking into account the Lorentzian broadening related to the 0169-4332r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S0169-4332 00 00219-1