Vertical Type Organic Device Using Thin-Film ZnO Transparent Electrode

Abstract

We propose a double heterojunction type organic light emitting diodes (OLED) using zinc oxide (ZnO) films, which works as a transparent and electron injection layer. The crystal structure of the ZnO films as a function of Ar/O₂ flow ratio and the basic characteristics of the OLED depending on the ZnO sputtering conditions are investigated. Excellent characteristics of novel OLED were obtained as high as 470cd/m²at 22V and 7.6mA/cm². The results obtained here demonstrate that the vertical type organic light emitting transistor (OLET) using ZnO layer as an electron injection layer is expected as a key element for flexible sheet displays.