Schottky and Metal-Insulator-Semiconductor Diodes Using Poly(3-hexylthiophene)

Abstract

The semiconducting polymer poly(3-hexylthiophene) (P3HT) has been previously used to fabricate Schottky barriers and metal-insulator-semiconductor (MIS) tunnel diodes using indium as the blocking contact. When P3HT is doped with FeCl₃, the conductivity increases and the polymer behaves as a p-type semiconductor. Schottky junctions fabricated on the doped material exhibited higher rectification ratios than equivalent junctions fabricated on undoped material. An indium contact evaporated on FeCl₃-doped P3HT film gave the current-voltage ( I-V) characteristics of a minority carrier tunnel diode. Similar I-V characteristics were observed when a thin insulating polymer film was placed between the indium contact and the doped P3HT film.