Metal-polymer schottky barriers on cast films of soluble poly(3-alkylthiophenes)

Abstract

We present the results of a study of strong rectification by metal-polymer (Schottky) diodes made by evaporating metal contacts onto films of a soluble semiconducting polymer cast from solution. Poly(3-hexylthiophene), a soluble alkyl derivative of poly(thiophene), and indium contacts from the Schottky diodes. Current-voltage characteristics exhibit rectification ratios in the range 100:1 to 1000:1; the forward current increases exponentially over several decades, whereas a relatively small leakage current flows under reversed bias. Capacitance-voltage data indicate nearly uniform dopant concentration over a depth of about 1500 Å.