Wet etching of non-polar gallium nitride light-emitting diode structure for enhanced light extraction

✍ Scribed by Hong-Yeol Kim; Younghun Jung; Sung Hyun Kim; Jaehui Ahn; Michael A. Mastro; Jennifer K. Hite; Charles R. Eddy Jr.; Jihyun Kim

• Book ID: 104022332
• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 639 KB
• Volume: 326
• Category: Article
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2011.01.053

✦ Synopsis

The surface of a non-polar a-plane GaN light-emitting diode (LED) was intentionally damaged with a KOH wet etch to enhance the extraction of light. This roughening technique has been commonly applied to c-plane polar GaN LEDs to extract photons that would otherwise suffer from total internal refraction. We show that wet etching of the non-polar LED does create a textured surface that increases the light extraction efficiency; however, the mechanism of the etch is quite dissimilar to the etch mechanism observed for c-plane LEDs. In fact, the etch proceeds perpendicular to the a-plane surface along unstable N-face (0 0 0 À 1) plane with the Ga-face plane resistant to the etch. The photoluminescence intensity from a-plane non-polar LED after KOH-based wet etching was increased by 83% in our experiments. Therefore, surface roughening by KOH-based wet etch was found to be very effective to extract photons from a-plane non-polar GaN-based LEDs.