Characteristics of Al doped ZnO co-sputtered InZnO anode films prepared by direct current magnetron sputtering for organic light-emitting diodes

Abstract

We studied the characteristics of aluminum zinc oxide (AZO) co-sputtered indium zinc oxide (IZO) anode films prepared by dual target direct current (DC) magnetron sputtering at room temperature in a pure Ar ambient environment. It was shown that the AZO co-sputtered IZO anode films exhibited comparable resistivity to pure IZO anode films eventhough AZO co-sputtered IZO has lower indium content. In addition, ultraviolet and visible spectrometer examination results showed that AZO co-sputtered IZO anodes have high transparency comparable to pure IZO anodes. Furthermore, AZO co-sputtered IZO shows a very smooth and featureless surface due to low substrate temperature during the cosputtering process. Using X-ray photoelectron spectroscopy depth profile examination, it was observed that the increase in DC power of the AZO target resulted in a significant decrease of the relative indium, element in the AZO co-sputtered IZO anode films. The current density-voltage-luminance (J-V-L) of the organic light light-emitting diodes (OLEDs) fabricated on an AZO co-sputtered IZO anode was similar to that of the OLED fabricated on a pure IZO anode. In addition, it was found that the J-V-L characteristics of the OLED were critically dependent on the sheet resistance of the AZO co-sputtered IZO anode. (c) 2008 Elsevier B.V. All rights reserved.