Hamburg 2001 – scientific programme
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O: Oberflächenphysik
O 38: Adsorption an Oberfl
ächen (IV)
O 38.4: Talk
Friday, March 30, 2001, 12:00–12:15, C
Electronic properties of Si surfaces during electrochemical deposition of organic molecules — •Prosper Hartig1, Joerg Rappich1, and Thomas Dittrich2 — 1Hahn-Meitner-Institut, Abt. Si-Photovoltaik, Kekulestr.5, D-12489 Berlin, Germany — 2Technische Universitaet Muenchen, Physik Department E16, D-85748 Garching, Germany
The electronic properties of Si surfaces are investigated in-situ by pulsed photovoltage and photoluminescence (PL) techniques during electrochemical deposition of organic molecules as diazonium salts. The elctrochemical preparation of the Si surfaces starts with well passivated and hydrogenated Si surfaces. The surface band bending and the quenching of radiative band-to-band recombination are probed stroboscopically. The surface band bending depends on the dipole moment of the grafted molecules. At the first moment, the electrochemical grafting of organic molecules leads only to roughly a doubling of the concentration of surface non-radiative recombination defects which decreases with further deposition time. The results demonstrate that the electrochemical formation of Si-C surface bonds does not lead to the formation of recombination active surface states in the forbidden gap of Si.