Figure 2: Impedance results versus frequency using 2 terminal test methode for clean and unclean Si substrates and APTES and Glutaraldehyude layers on top. –✩–: Results on cleaned Si substrate, –✶– : results on uncleaned Si substrate, Δ: Results on APTES surface on cleaned Si substrate, ▲: Results on APTES surface on uncleaned Si substrate, ○: Results on Glutaraldehyde surface on cleaned Si substrate, ●: Results on Glutaraldehyde surface on uncleaned Si substrate. (a): Impedance Z versus frequency f, (b) Capacitance C versus frequency f.