Influence of water and electrolyte included in the polymer on the rectifying properties of the junction n-doped silicon/poly(4,4′-dipentoxy-2,2′-bithiophene)

Small amounts of water and electrolyte included in the polymer during the electrochemical polymerization, and detected by thermogravimetric analysis and X-ray diffraction strongly affect the current-voltage characteristics of the system n-doped silicon/poly(4,4′-dipentoxy-2,2′-bithiophene). Current-voltage curves and impedance measurements demonstrated that a double layer is established at the interface relative to the electric contact on the polymer where, probably, the oxidation of water takes place when the rectifying junction is forward biased. These processes affect the transport properties of the junction in different ways, depending on the nature of the contact. It was also found that the properties of the silicon/polymer interface do not depend meaningfully on eventual amounts of water and electrolyte included in the polymer.