Effects O2 plasma surface treatment on the electrical properties of the ITO substrate

• Published in: Journal of the Korean Physical Society Vol. 60; no. 10; pp. 1576 - 1581
• Main Authors: Hong, Jin-Woong, Oh, Dong-Hoon, Shim, Sang-Min, Lee, Young-Sang, Kang, Yong-Gil, Shin, Jong-Yeol
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.05.2012; 한국물리학회
• Subjects: Mathematical and Computational Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Theoretical; 물리학; Cole-Cole plot; Conductive mechanism; Plasma treatment; Surface resistance; ITO surface
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.60.1576

The indium-tin-oxide (ITO) substrate is used as a transparent electrode in organic light-emitting diodes (OLEDs) and organic photovoltaic cells. The effect of an O 2 plasma surface treatment on the electrical properties of the ITO substrate was examined. The four-point probe method, an atomic force microscope (AFM), a LCR meter, a Cole-Cole plot, and a conductive mechanism analysis were used to assess the properties of the treated ITO substrates. The four-point probe method and the AFM study revealed a lower ITO surface resistance of 17.6 Ω/sq and an average roughness of 2 nm, respectively, for a substrate treated by a plasma at 250 W for 40 s. The lower surface resistance of the ITO substrate treated at 250 W for 40 s was confirmed by using a LCR meter. An amorphous fluoropolymer (AF) was deposited on an ITO substrate treated under the optimal conditions and on a non-plasma treated ITO substrate as well. The potential barriers for charge injection in these devices were 0.25 eV and 0.15 eV, respectively, indicating a 0.1-eV decrease due to the plasma treatment.