標題: High performance 380-nm ultraviolet light-emitting-diodes with 3% efficiency droop by using free-standing GaN substrate manufacturing from GaAs substrate
作者: Shieh, Chen-Yu
Tsai, Ming-Ta
Li, Zhen-Yu
Kuo, Hao-Chung
Chang, Jeng-Yang
Chi, Gou-Chung
Lee, Wei-I
電子物理學系
光電工程學系
Department of Electrophysics
Department of Photonics
關鍵字: free-standing GaN substrate;ultraviolet light-emitting-diodes;atmospheric pressure metal-organic chemical vapor deposition;high-resolution double crystal x-ray diffraction;transmission electron microscopy;light output power;efficiency droop
公開日期: 7-七月-2014
摘要: We investigated the influence of free-standing GaN (FS-GaN) substrates on the performance of ultraviolet light-emitting-diodes (UV-LEDs) grown on top by atmospheric pressure metal-organic chemical vapor deposition. High-resolution double-crystal x-ray diffraction (HRDCXD) analysis demonstrated high-order satellite peaks and clear fringes between them for UV-LEDs grown on the FS-GaN substrate, from which the interface roughness was estimated. In addition, the full width at half maximum of the HRDCXD rocking curve in the (0002) and the (1012) reflections were reduced to below 90 arc sec. The Raman results indicated that the GaN-based epilayer of strain free was grown. Additionally, the effect of the FS-GaN substrate on the crystal quality of the UV-LEDs was examined in detail by transmission electron microscopy (TEM). The TEM characterizations revealed no defects and V-pits were found in the scanned area. Based on the results mentioned above, the light output power of UV-LEDs on the FS-GaN substrate can be enhanced drastically by 80% and 90% at 20 and 100 mA, respectively. Furthermore, an ultralow efficiency degradation of about 3% can be obtained for the UV-LEDs on the FS-GaN substrate at a high injection current. The use of an FS-GaN substrate is suggested to be effective for improving the emission efficiency and droop of UV-LEDs grown thereon.
URI: http://dx.doi.org/10.1117/1.JNP.8.083081
http://hdl.handle.net/11536/24612
ISSN: 1934-2608
DOI: 10.1117/1.JNP.8.083081
期刊: JOURNAL OF NANOPHOTONICS
Volume: 8
Issue: 
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