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  Yang, F.; Hunger, R.; Rademann, K.; Rappich J.: Photoluminescence and surface photovoltage of ethynyl derivative-terminated Si(111) surfaces. Physica Status Solidi C 7 (2010), p. 161-164

10.1002/pssc.200982474

Abstract:
Since the last past years, organic functionalization of semiconductor surfaces, especially for silicon (Si), has received a tremendous interest in the development of organic/semiconductor hetero-structures [1]. In this work, direct electrochemical deposition (grafting) of organic layers (molecules) like methyl groups (CH3/CD3) and ethynyl derivatives (C≡CH, C≡C−CH3, C≡C−C6H5) onto Si(111) surfaces have been performed in a one-step process by anodic treatment in Grignard electrolytes. Grafting of ethynyl derivatives lead to the formation of polymeric layers where the thickness (which was in the nm range) depends on charge flow, while methyl groups lead to a monolayer on Si(111) surfaces. The vibrational and electronic properties of such organic/Si interfaces have been investigated using spectroscopic methods like infrared spectroscopic ellipsometry (IRSE), synchrotron X-ray photoemission spectroscopy (SXPS), to examine the chemical species present on the surfaces. Moreover, pulsed photoluminescence (PL) spectroscopy permits to characterize the number of non-radiative active defects at the interface.