On the impedance of the silicon dioxide/electrolyte interface

摘要: The small-signal impedance of electrolyte/insulator/silicon structures is partly determined by the properties insulator/electrolyte interface. A theoretical model for this interfacial derived. Two parallel contributions are involved: double-layer capacitance, which a Gouy-Chapman-Stern adopted, and branch containing capacitance related to surface reactions with H+ OH− ions from electrolyte. These cause total be very low insulators high reactivity such as, instance, Al2O3 or Ta2O5. For SiO2 surfaces, much lower, implying larger impedance. Measurements were carried out at frequencies on 12 nm layers in NaCl electrolytes ionic strengths 10−4, 10−3and 10−2 M. results agreed predictions based parameter values obtained independent measurements ψ0/pH characteristics. agreement confirms formation charge through fixed silanol groups surface.