Electronic and optical properties of electrochemically polymerized polycarbazole/aluminum Schottky diodes

Abstract

We report the fabrication of organic Schottky diodes on indium tin oxide (ITO) coated glass by electrochemically polymerized polycarbazole (PCz) with configuration ITO/PCz/Al. The diode has been characterized in respect of electrical and optical properties. The study involves estimation of optical bandgap of the polymer from UV-visible spectroscopic measurements. The current-voltage (J-V) and capacitance-voltage (C-V) characteristics of the Schottky diode were subsequently used for extracting electronic parameters of the device such as ideality factor, barrier height, reverse saturation current, built-in potential, depletion width, doping concentration, etc. The photoresponse of the Schottky contact was measured by illuminating the device with a laser source operating at 650 nm having an incident optical power density of 10 mW/ cm2. The device exhibits a high value of peak detectivity (∼107 cm Hz1/2 W-1) near zero bias voltage and the same attains a value of the order of 109 cm Hz1/2 W-1 at a reverse bias of -6 V. © 2009 American Institute of Physics.