The electrochemical fabrication of a hybrid inorganic-organic field effect transistor ͑IOFET͒ is described. Ti-Zr mixed oxide ͑dielectric permittivity ϳ45͒ grown by anodizing has been used as a dielectric, while 3,4-polyethylenedioxythiophene has been employed as a semiconducting polymer. The polymerization of 3,4-ethylenedioxythiophene on the oxide has been realized by a photoelectrochemical process. The metal/oxide/polymer junctions have been investigated by photocurrent spectroscopy and scanning electron microscopy. The output transistor characteristics have been recorded in order to test the performance of the junctions in the IOFET structure.After discovery of conducting polymers and the possibility to modify their electrical properties ͑from insulating to metallic like behavior͒ by doping and a careful choice of the processing conditions, a large amount of research effort has been devoted to the theoretical understanding of their solid state properties as well as to exploit the possible application of conducting polymers in many technological fields including large area organic electronics, polymer photovoltaic cell, and sensors. 1-4 Organic thin film transistors appear very promising devices for the development of low cost, flexible, and disposable plastic electronics. In order to reduce the operating voltage it has been suggested in the literature to use mixed inorganic-organic thin film transistors by assembling a structure formed by metal ͑bottom contact͒/dielectric layer ͑gate͒/organic semiconductor/top contact ͑source/drain͒. According to this, a wet electrochemical route appears to be very promising in terms of cost, at least for the preparation of thin ͑thickness Ͻ10 nm͒ or thick ͑thickness Ͼ10 nm͒ oxide films by anodizing in aqueous electrolytes. Moreover, by taking into account the possibility to grow semiconducting polymers on wide bandgap dielectric oxide ͑Ta 2 O 5 ͒ by a photoelectrochemical route, which has been shown recently, 5,6 it seems very appealing to exploit an integral electrochemical route to fabricate advanced inorganic/organic hybrid structure which could be used as a building block for a field effect transistor ͑FET͒ junction.In this paper, we describe and discuss the electrochemical fabrication of a hybrid structure to be used in the production of an inorganic-organic field effect transistor ͑IOFET͒ using 3,4-polyethylenedioxythiophene ͑PEDOT͒ as a semiconducting polymer and anodic films grown on the Ti-10 atom % Zr alloy as dielectrics. The choice of the oxide is based on its low dark current value and quite high photocurrent intensity, under monochromatic light, at not too high anodic potential and photon energy, 7 as well as on its high dielectric permittivity ͑ϳ45, according to Ref. 8͒. The metal/oxide/ polymer junctions are investigated by photocurrent spectroscopy ͑PCS͒ and scanning electron microscopy ͑SEM͒. Finally, output transistor characteristics are recorded in order to test the performance of the junctions in the IOFET structure.
ExperimentalTi-10 atom % Zr alloys we...