1. Nanoscale Characterization of V-Defect in InGaN/GaN QWs LEDs Using Near-Field Scanning Optical Microscopy.
- Author
-
Li, Yufeng, Tang, Weihan, Zhang, Ye, Guo, Maofeng, Li, Qiang, Su, Xilin, Li, Aixing, and Yun, Feng
- Subjects
- *
NEAR-field microscopy , *QUANTUM efficiency , *QUANTUM wells , *ATOMIC force microscopy , *CURRENT distribution - Abstract
The size of the V-defects in the GaN/InGaN-based quantum wells blue light-emitting diode (LED) was intentionally modified from 50 nm to 300 nm. High resolution photoluminescence and electroluminescence of a single large V-defect were investigated by near-field scanning optical microscopy. The current distribution along the {10-11} facets of the large defect was measured by conductive atomic force microscopy. Nearly 20 times the current injection and dominant emission from bottom quantum wells were found in the V-defect compared to its vicinity. Such enhanced current injection into the bottom part of quantum wells through V-defect results in higher light output power. Reduced external quantum efficiency droops were achieved due to more uniform carrier distribution. The un-encapsulated fabricated chip shows light output power of 172.5 mW and 201.7 mW at 400 mA, and external quantum efficiency drop of 22.3% and 15.4% for the sample without and with large V-defects, respectively. Modified V-defects provide a simple and effective approach to suppress the efficiency droop problem that occurs at high current injection, while improving overall quantum efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF