標題: Characterization of 380 nm UV-LEDs grown on free-standing GaN by atmospheric-pressure metal-organic chemical vapor deposition
作者: Shieh, C. Y.
Li, Z. Y.
Kuo, H. C.
Chang, J. Y.
Chi, G. C.
光電工程學系
Department of Photonics
關鍵字: indium clustering;internal quantum efficiency;efficiency droop;free-standing GaN substrate;UV LEDs
公開日期: 1-Jan-2014
摘要: We reported the defects and optical characterizations of the ultraviolet light-emitting diodes grown on free-standing GaN substrate (FS-GaN) and sapphire. Cross-sectional transmission electron microscopy (TEM) images showed that the total defect densities of grown UV LEDs on FS-GaN and sapphire including edge, screw and mixed type were 3.6x10(6) cm(-2) and 5.5x10(8) cm(-2). When substrate of UV LEDs was changed from sapphire to FS-GaN, it can be clearly found that the crystallography of GaN epilayers was drastically different from that GaN epilayers on sapphire. Besides, the microstructures or indium clustering can be not observed at UV LEDs on FS-GaN from TEM measurement. The internal quantum efficiency of UVLEDs on FS-GaN and sapphire were 34.8 % and 39.4 % respectively, which attributed to indium clustering in multi-layers quantum wells (MQWs) of UV LEDs on sapphire. The relationship between indium-clustering and efficiency droop were investigated by temperature-dependent electroluminescence (TDEL) measurements.
URI: http://dx.doi.org/10.1117/12.2039621
http://hdl.handle.net/11536/134718
ISBN: 978-0-8194-9899-1
ISSN: 0277-786X
DOI: 10.1117/12.2039621
期刊: GALLIUM NITRIDE MATERIALS AND DEVICES IX
Volume: 8986
起始頁: 0
結束頁: 0
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