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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications
SYSA 5: Poster Session SYSA
SYSA 5.68: Poster
Tuesday, February 26, 2008, 14:30–20:00, Poster A
Vibrational and electronic properties of methylated silicon (111) surfaces in air — •Florent Yang1, Ralf Hunger2, Katy Roodenko3, Karsten Hinrichs3, Klaus Rademann4, and Jörg Rappich1 — 1Hahn-Meitner-Institut Berlin, Dep. Si-Photovoltaics (SE1), Berlin, Germany — 2Technische Universität Darmstadt, Institute of Materials Science, Darmstadt, Germany — 3Institute of Analytical Sciences, Department Berlin, Germany — 4Humboldt University Berlin, Department of Chemistry, Berlin, Germany
Controlling and monitoring the grafting of small organic molecule onto silicon (Si) surfaces is the centre of sustained efforts of many research groups. These investigations are widely motivated by the fabricating hybrid devices and sensors. The control of the work function, the creation of surface dipole, and the change in band bending obtained by an organic layer on Si is of great interest also for hetero-structure solar cells. Our work concerns the direct deposition of CH3/CD3 groups on flat hydrogenated p-Si(111) surfaces by anodisation in a Grignard reagent. The ultrathin films have been characterised by different techniques like IR-SE, AFM, XPS/UPS to obtain information about the thickness, the topography and the type of chemical bonds of the organic films on the surface. PL spectroscopy was used to investigate the recombination behaviour at such interfaces. Methylated Si surfaces show low surface recombination velocities and are not susceptible to rapid oxidation in ambient air. These modified surfaces passivate the Si towards oxidation and exhibit a much better stability than H-terminated Si surfaces in ambient air.