Greffage D'un sel de diazonium a la surface du silicium de type p-Si(111) et caracterisation par spectroscopie ir in-situ

To stabilize the hydrogenated surface of the silicon and confer it a resistance on the oxidation, we proceeded to the modification of its chemical nature. The Si samples were prepared from p-type, medium doped (resistivity 10 Ω.cm) single crystal wafers of (111) orientation. So, we transplanted by electrochemical reduction the benzendiazonium 4-Br to the surface of the silicon in aqueous middle containing HF and H₂SO₄, the peak obtained in the potential -0.195V/E.C.S confirming the grafting. This surface so modified was characterized by spectroscopy IR in - situ in order to follow the changes in real time. The percentage of grafting reached 60 % because it is limited by steric hindrance which is due to the replacement of the hydrogen by a radical. This study also allowed us to envisage a mechanism of grafting.