| AVS 63rd International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF-ThP |
| Session: | Thin Films Poster Session |
| Presenter: | Midori Kawamura, Kitami Institute of Technology, Japan |
| Authors: | M. Kawamura, Kitami Institute of Technology, Japan T. Chiba, Kitami Institute of Technology, Japan T. Kiba, Kitami Institute of Technology, Japan Y. Abe, Kitami Institute of Technology, Japan K.H. Kim, Kitami Institute of Technology, Japan |
| Correspondent: | Click to Email |
Transparent conductive films are widely used as electrodes in solar cells and display devices. As a material, indium tin oxide (ITO) has been most popular. However, development of indium-free or indium-saving materials is also demanded. As one of the solutions, a multilayer structure with oxide/metal/oxide layers has been developed. Previously, we have prepared indium zinc oxide (IZO)/Ag/IZO multilayer as an anode of an OLED, and obtained an excellent properties. In the present paper, we prepared an indium-free multilayer consists of molybdenum oxide (MoO3) and Ag. We report a properties of the multilayer as a transparent conductive film and as an anode of OLED.
Film deposition was conducted on a glass substrate at room temperature by vacuum evaporation method. The thicknesses of the Ag layer and the MoO3 layer were varied from 10 to 14 nm and 5 to 30 nm, respectively. The figure of merit (FOM) was calculated based on the sheet resistance and transmittance at a wavelength of 550 nm to estimate the performance of the transparent conductive films. The OLEDs consists of anode/MoO3(1nm)/α-NPD(60,70nm)/Alq3(65, 75nm)/LiF(1nm)/Al(150nm) were fabricated and the current [http://ejje.weblio.jp/content/current+of+electricity] and the luminance of the devices as a function of applied voltage were measured.
Sheet resistance of the multilayer was mainly governed by thickness of the Ag layer, therefore multilayer where the thickness of Ag layer was 14 nm showed low values. However, optical transmittance at a wavelength of 550nm changed depending on the thickness of oxide layer, and the highest FOM value was obtained in a multilayer consists of MoO3(30nm)/Ag(14nm)/MoO3(30nm). By AFM observation, it was found that hillocks were formed on the multilayer surface and this caused a short-circuit of an OLED device. Finally, we obtained a good OLED properties by increasing thicknesses of organic layers. It is found that efforts to reduce surface roughness of the multilayer is needed to improve OLED properties further.