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Functionalisation of Si surfaces by organic molecules is of high interest for a wide range of possible applications such as Si based sensors [1-3], photovoltaics [4], microelectronics [5, 6] or bio-chips [7]. Hydrogenated Si(111) surfaces have a low rate of surface charge carrier recombination, which means that this sur-face is well-passivated [8]. However, this surface is not stable and oxidizes rapidly in contact with ambient air [9]. For this reason, a way to avoid this degradation is to form covalent Si-C bonds which can be obtained by various methods initiated chemically [10], electrochemically [11, 12], thermally [13] or photochemically [14]. Such modi-fied surfaces are expected to exhibit a better chemical sta-bility and good electronic passivation (low concentration of interface states in the band gap) [15, 16]. Pulsed PL and SPV are two complementary methods to obtain informa-tions about the amount of non-radiative active defect cen-ters at the interface and to measure the minority carrier lifetime and diffusion length [17, 18]. In this work, electrochemical processing has been cho-sen as method to graft ethynyl derivatives onto Si(111) sur-faces by the use of Grignard reagents. Recently, it has been shown that this electrochemical grafting method lead to formation of polymeric layers with thicknesses of about 10-20 nm when a charge flow of 450 mC/cm

In the Anderson model the alignment of electronic energy levels follows from the assumption that the vacuum-levels of the contacting phases are at equal height. Engineering of the line up may be attempted by changing the ionization energy of the substrate and/or of the adsorbate. We report on the variation of the Si(111) ionization energy by induced surface dipoles of –CH3, –H, and –GaSe terminations and the induced variation of the HOMO line up of PTCDA and ZnPc layers. In addition the variation of the line up by changing the organic molecule ionization energy is exemplified by F substitution in ZnPc. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We report the results of an investigation of the interaction between Se and Ru in Ru−Se electrocatalysts showing high activity and methanol tolerance in the oxygen reduction reaction (ORR). The res...