Mechanisms of lighting enhancement of Al nanoclusters-embeddedAl-doped ZnO film in GaN-based light-emitting diodes

• Published in: Journal of applied physics 2010-01, Vol.107 (1), p.014503-014503-5
• Main Authors: Lee, Hsin-Ying, Chou, Ying-Hung, Lee, Ching-Ting, Yeh, Wen-Yung, Chu, Mu-Tao
• Format: Article
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3276092

Aluminum (Al)-doped ZnO (AZO) films with embedded Al nanoclusters were proposed and utilized to enhance the light output power and maximum operation current of GaN-based light-emitting diodes (LEDs). The AZO films were sputtered using ZnO and Al targets in a magnetron cosputtering system. With Al dc power of 7 W and ZnO 100 W ac power, the electron concentration of 4.1 × 10 20   cm − 3 , electron mobility of 16.2   cm 2 / V s , and resistivity of 7.2 × 10 − 4   Ω cm were obtained for the deposited AZO film annealed at 600 ° C for 1 min in a N 2 ambient. As verified by a high resolution transmission electron microscopy, the deposited AZO films with embedded Al nanoclusters were clearly observed. A 35% increase in light output power of the GaN-based LEDs with Al nanoclusters-embedded AZO films was realized compared with the conventional LEDs operated at 500 mA. It was verified experimentally that the various characteristics of GaN-based LEDs including the antireflection, light scattering, current spreading, and the light extraction efficiency in light emission could be significantly enhanced with the use of Al nanoclusters-embedded AZO films.