High efficiency and improved ESD characteristics of GaN-based LEDs with naturally textured surface grown by MOCVD

• Published in: IEEE photonics technology letters Vol. 18; no. 11; pp. 1213 - 1215
• Main Authors: Tsai, C.M., Sheu, J.K., Wang, P.T., Lai, W.C., Shei, S.C., Chang, S.J., Kuo, C.H., Kuo, C.W., Su, Y.K.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2006; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Chemical vapor deposition; Contact; Efficiency; Electric potential; Electrostatic discharge; Electrostatic discharge (ESD); Electrostatic discharges; Emittance; Gallium nitride; GaN light-emitting diode (LED); Insertion; Light emitting diodes; MOCVD; Organic chemicals; Power generation; Rough surfaces; Surface chemistry; Surface discharges; Surface roughness; Surface texture; textured surfaces; Threading dislocations; V-shaped pits; Voltage
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2006.875063

The following paper presents a study on GaN-based light-emitting diodes (LEDs) with naturally textured surface grown by metal-organic chemical vapor deposition. The study utilizes a well-known approach of increasing light extraction efficiency. The approach is based on naturally formed V-shaped pits on surface that originate from low-temperature-growth (LTG) conditions of topmost p-GaN contact layer. In our experiment, the high-temperature-grown (HTG) p-GaN layer was inserted between the p-AlGaN electron-blocking layer and the LTG p-GaN contact layer, in order to suppress pit-related threading dislocations (TDs). These TDs may intersect the underlying active layer. The results of the experiment show that GaN-based LEDs with the HTG p-GaN insertion layer can effectively endure negative electrostatic discharge voltage of up to 7000 V. We also noted that application of 20-mA current injection yields output power of about 16 mW for the LEDs emitting around 465 nm. The output power results correspond to an external quantum efficiency of around 30%