Device Characteristics of Top-Emitting Organic Light-Emitting Diodes Depending on Anode Materials for CMOS-Based OLED Microdisplays

• Main Authors: Hyunkoo Lee, Hyunsu Cho, Chun-Won Byun, Chan-Mo Kang, Jun-Han Han, Jeong-Ik Lee, Hokwon Kim, Jeong Hwan Lee, Minseok Kim, Nam Sung Cho
• Format: Article
• Language: English
• Published: IEEE 2018-01-01
• Series: IEEE Photonics Journal
• Subjects: Organic light-emitting diodes (OLEDs); microdisplay; OLEDoS; CMOS
• Online Access: https://ieeexplore.ieee.org/document/8502212/

We investigated the optical reflectance, surface roughness, and sheet resistance of aluminum (Al)/titanium nitride (TiN), titanium (Ti), and tungsten (W) layers on Si substrates, which are available in the CMOS foundry, for organic light-emitting diode (OLED) microdisplays. The devices with different metal anode layers exhibited different hole-injection properties and OLED performances, owing to the different optical and electrical properties of metal anode layers. Based on the OLED characteristics, the Al/TiN layer was selected as an anode layer for OLED microdisplays. A green monochromatic OLED microdisplay panel was designed and implemented using the 0.11-μm CMOS process. The density of pixels was ~2 351 pixels per inch and the panel's active area was 0.7 in in diagonal. The resolution of the panel was 1 280 × 3 × 1 024, corresponding to SXGA. The panel was successfully operated, and the maximal luminance was ~460 cd/m².