Current–voltage and capacitance–voltage characteristics of Al/p-type silicon/organic semiconductor based on phthalocyanine rectifier contact

Abstract

Electrical characteristics of the Al/p-type silicon/2,9,16,23-tetrakis-{6-(-thiophene-2-carboxylate)-hexylthio}phthalocyaninato cobalt(II) organic semiconductor contact have been investigated by current–voltage and capacitance–voltage measurements. The ideality factor (1.33), barrier height (0.90 eV) and series resistance (314.5 kΩ) of the Al/p-Si/CoPc contact were obtained from current–voltage characteristics. The barrier height obtained for the Al/p-Si/CoPc diode is significantly higher than that of obtained for the conventional Al/p-Si Schottky diode. The CoPc organic layer modifies the effective barrier height of Al/p-Si Schottky diode as the organic film forms a physical barrier between Al metal and the p-Si. The interface-state density of the diode was determined and interface-state density was found to vary from 1.23 × 10 14 eV − 1 cm − 2 to 0.69 × 10 14 eV − 1 cm − 2 . It is evaluated that the CoPc organic layer modifies electrical parameters and interface properties of Al/p-Si junction.