Improvement of GaN light-emitting diodes with surface-treated Al-doped ZnO transparent Ohmic contacts by holographic photonic crystal

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2012-06, Vol.107 (4), p.809-812
• Main Authors: Yang, W. F., Liu, Z. G., Xie, Y. N., Cai, J. F., Liu, S., Gong, H., Wu, Z. Y.
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Condensed Matter Physics; Electronics; Exact sciences and technology; Machines; Manufacturing; Nanotechnology; Optical and Electronic Materials; Optoelectronic devices; Physics; Physics and Astronomy; Processes; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Surfaces and Interfaces; Thin Films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-012-6874-x

This letter presents a holographic photonic crystal (H-PhC) Al-doped ZnO (AZO) transparent Ohmic contact layer on p-GaN to increase the light output of GaN-based LEDs without destroying the p-GaN. The operating voltage of the PhC LEDs at 20 mA was almost the same as that of the typical planar AZO LEDs. While the resultant PhC LED devices exhibited significant improvements in light extraction, up to 1.22 times that of planar AZO LEDs without PhC integration. Temperature dependence of the integrated photoluminescence intensity indicates that this improvement can be attributed to the increased extraction efficiency due to the surface modification. These results demonstrate that the surface-treated AZO layer by H-PhCs is suitable for fabricating high-brightness GaN-based LEDs.