Pulsed Nd:YAG laser depositions of ITO and DLC films for OLED applications

摘要

Indium-tin oxide (ITO) films deposited on heated and non-heated glass substrates by a pulsed Nd:YAG laser at 355 nm and ～2.5 J/cm~2 were used in the fabrication of simple organic light-emitting diodes (OLEDs), ITO/(PVK + Alq_3 + TPD)/Al . The ITO was deposited on heated glass substrates which possessed resistivity as low as ～3 × 10~(-4) Ω cm, optical transmission as high as ～92% and carrier concentration of about ～5 × 10~(20) cm~(-3), were comparable to the commercial ITO. Substrate heating transformed the ITO microstructure from amorphous to polycrystal-line, as revealed by the XRD spectrum. While the polycrystalline ITO produced higher OLED brightness, it was still lower than that on the commercial ITO due to surface roughness. A DLC layer of ～ 1.5 nm deposited on this ITO at laser fluence of > 12.5 J/cm~2 improved its device brightness by suppressing the surface roughness effect.