This work shows the results obtained for the silicon modification with redox molecules derived from ferrocene. The effect of the crystallographic orientation of silicon on the electron-transfer rates was studied. For this study, silicon electrodes (p-type) with two different crystallographic orientations were employed: p-Si (100) and p-Si (111). The redox molecules employed were alkyl ferrocenes with 3, 5 and 10 carbon atoms (propyl, pentyl and decyl ferrocene, respectively). The results showed that the electron-transfer process is not influenced by the crystallographic orientation of silicon and that this process is determinate by electron hopping in a regime of bonded diffusion.