Adsorption and decomposition of C60 on Ni(110) surfaces

In the present paper we study the adsorption of C-60 on Ni(110) surfaces at RT and 650 K, as well as the desorption/decomposition process. The investigation took place in UHV by means of Auger electron spectroscopy, low energy electron diffraction, thermal desorption spectroscopy and work function (WF) measurements. The observed overlayer structures during C-60 deposition at 650 K are in complete agreement with reported results. The sticking coefficient is nearly the same for both RT and 650 K. Heating of the 1 ML C-60-covered Ni(110) surface, however, at 750 K, causes a partial fragmentation of C-60 to a 2D graphite-like layer, while the remaining C-60 molecules are rearranged in the (5 x 3) structure, in contrast to reported results. Further heating to 800 K results in the complete fragmentation of C-60 accompanied by carbon desorption, possibly in molecular C-n (n > 10) form. Above 800 K, the C of the graphite-like layer is desorbed in both atomic and molecular form. The WF at saturation coverage was found to be 5.61 eV for both deposition at RT and 650 K. This value is substantially greater than the average value of 5 eV, which has been suggested to hold for C-60 overlayer systems, regardless of the metal substrate. (C) 2001 Elsevier Science B.V. All rights reserved.