Enhancement of charge injection in an organic thin-film transistor with a metal-oxide multilayer electrode

초록

We studied the effect of insertion of metal-oxide layers into electrodes for OTFTs (organic thin film transistors) to improve their electrical characteristics. The thickness of pentacene was about 50 nm and the metal electrode was made of gold. The metal-oxide thin-film layers inserted between the electrode and the organic pentacene layers were about 2-8 nm and the electrical properties of the inserted metal-oxide layers were measured by using UPS (ultraviolet photoelectron spectroscopy). From the results for the electrical properties, the mobility and the threshold voltage of the OTFTs with inserted WO<inf>3</inf> layers were improved from 8.80 × 10-3 cm2/V·s to 2.48 × 10-2 cm2/V·s and were decreased from -12.3 V to -4.09 V, respectively. The mobility and the threshold voltage of the OTFTs with inserted TiO<inf>2</inf> layers were decreased to 7.04 × 10-3 cm2/V·s and -3.38 V, respectively. From the results of the UPS analysis, we found that the inserted WO<inf>3</inf> layers decreased and TiO<inf>2</inf> layers increased the energy barriers at the interface between the electrode and the organic pentacene layers. © 2017, Korean Physical Society. All rights reserved.