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Enhancement of Charge Injection in an Organic Thin-Film Transistor with a Metal-Oxide Multilayer Electrode
New Physics: Sae Mulli 2017; 67: 24~29
Published online January 31, 2017;
© 2017 New Physics: Sae Mulli.

YeongHun JEONG1, Hyeonwook JANG1, Hyeji HAN1, Sunghoon JEON1, Shant ARAKELYAN1, Hanju LEE1, Kiejin LEE*1, Donghoon OH2, Deokjoon CHA2

1 Department of Physics, Sogang University, Seoul 04107, Korea
2 Department of Physics, Kunsan National University, Kunsan 54050, Korea
Correspondence to:
Received September 22, 2016; Revised September 29, 2016; Accepted September 29, 2016.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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$\sim$8 nm and the electrical properties of the inserted metal-oxide layers were measured by using UPS (ultraviolet photoelectron spectroscopy). From the results for the electrical properties, the mobility and the threshold voltage of the OTFTs with inserted WO$_3$ layers were improved from 8.80 $\times$ 10$^{-3}$ cm$^2$/V$\cdot$s to 2.48 $\times$ 10$^{-2}$ cm$^2$/V$\cdot$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$_2$ layers were decreased to 7.04 $\times$ 10$^{-3}$ cm$^2$/V$\cdot$s and -3.38 V, respectively. From the results of the UPS analysis, we found that the inserted WO$_3$ layers decreased and TiO$_2$ layers increased the energy barriers at the interface between the electrode and the organic pentacene layers.
PACS numbers: 73.30.+y
Keywords: Pentacene, Organic thin-film transistor

October 2017, 67 (10)
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