Light Extraction and Auger Recombination in AlGaN-Based Ultraviolet Light-Emitting Diodes
Author(s): Ni, RX (Ni, Ruxue); Yu, ZG (Yu, Zhiguo); Liu, Z (Liu, Zhe); Zhang, L (Zhang, Lian); Jia, LF (Jia, Lifang); Zhang, Y (Zhang, Yun)
Source: IEEE PHOTONICS TECHNOLOGY LETTERS Volume: 32 Issue: 16 Pages: 971-974 DOI: 10.1109/LPT.2020.3006863 Published: AUG.15, 2020
Abstract: AlGaN-based 300-nm ultraviolet (UV) light-emitting diodes (LEDs) with various p-n junction mesa perimeter-to-area (P/A) ratios and mesa depths were fabricated. As the mesa P/A ratio increases from 0.0133 mu m(-1) to 0.157 mu m(-1) and the mesa depth increases from 550 nm to 1700 nm, the peak external quantum efficiency (EQE) increases from 2.93% to 4.89%. Fitting results from the ABC+f(n) model reveal that the light-extraction efficiency (LEE) is the major factor limiting the EQE, which can be enhanced by increasing the mesa P/A ratio and mesa depth. On the other hand, increasing the mesa P/A ratio and mesa depth also leads to increased Auger recombination coefficient from 1.11 x 10(-31) cm(6)s(-1) to 2.11 x 10(-30) cm(6)s(-1), and the probable mechanism is defect-assisted Auger recombination at mesa sidewall by etching damage. In spite of the decreased internal quantum efficiency by Auger recombination, the improved LEE by increasing the mesa P/A ratio and mesa depth is still the major factor for the EQE at the current density below 150 A/cm(2) for UV LEDs.
Accession Number: WOS:000550641300002
ISSN: 1041-1135
eISSN: 1941-0174
