The growth of ultrathin Cr films on benzene-covered Ni(111)

• Published in: Applied surface science Vol. 142; no. 1; pp. 327 - 331
• Main Authors: Sklarek, W, Held, G, Ammon, C, Steinrück, H.-P
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.1999; Elsevier Science
• Subjects: Benzene; Chromium; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Organo-metallic compounds; Physics; Thin film growth; XPS; Organo-metallic compounds; 82.80.Ej; BF; Thin film growth; 81.15.Hi; CN; TG; NC; TI; Benzene; PG; Chromium; XPS; 68.55.Nq; OBM; 82.65.−i; Ultrathin films; Annealing; Transition elements; Thermodesorption; Experimental study; Vacuum evaporation; Film growth; Preadsorption; X-ray photoelectron spectra
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(98)00737-5

Using X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD) we studied the properties of thin Cr films in the nominal coverage range between 0.13 and 4 monolayers (ML), which were evaporated onto a Ni(111) surface pre-covered with up to 14 ML benzene. Evaporation of small amounts of Cr (<0.5 ML) onto thick benzene layers (>4 ML) at 100 K leads to the formation of non-metallic bis(benzene)chromium (Cr(C 6H 6) 2) rather than condensation of small clusters in the benzene matrix, as can be seen from the positions and shapes of the Cr 2p 3/2 peaks in XPS. Upon annealing to 400 K these films transform into metallic Cr as is indicated by a Cr 2p 3/2 peak shift of −0.8 eV, and significant changes in the peak shapes. For 0.5–2 ML a metallic Cr species, in addition to the non-metallic species, is already seen at 100 K. For higher coverages >2 ML only the metallic species is seen in XPS and the Cr 2p 3/2 peak shape does then not change upon annealing. The development of the C 1s spectra upon annealing reveals that there is a significant amount of benzene buried under the Cr layer, which is partially dissociated, depending on the annealing temperature and the Cr coverage.