Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Influence of carrier localization on high-carrier-density effects in AlGaN quantum wells

Open Access Open Access

Abstract

The influence of carrier localization on photoluminescence efficiency droop and stimulated emission is studied in AlGaN multiple quantum wells with different strength of carrier localization. We observe that carrier delocalization at low temperatures predominantly enhances the nonradiative recombination and causes the droop, while the main effect of the delocalization at elevated temperatures is enhancement of PL efficiency due to increasing contribution of bimolecular recombination of free carriers. When the carrier thermal energy exceeds the dispersion of the potential fluctuations causing the carrier localization, the droop is caused by stimulated carrier recombination.

© 2014 Optical Society of America

Full Article  |  PDF Article
More Like This
Dynamics of nonequilibrium carrier decay in AlGaN epitaxial layers with high aluminum content

Tanuj Saxena, Michael Shur, Saulius Nargelas, Žydrūnas Podlipskas, Ramūnas Aleksiejūnas, Gintautas Tamulaitis, Max Shatalov, Jinwei Yang, and Remis Gaska
Opt. Express 23(15) 19646-19655 (2015)

Quantum confinement dependence of exciton localization in a-plane GaN/AlGaN multiquantum wells investigated by temperature dependent photoluminescence

Feng Wu, Jun Zhang, Shuai Wang, Hanling Long, Jiangnan Dai, Zhe Chuan Feng, Zheng Gong, and Changqing Chen
Opt. Mater. Express 5(11) 2608-2615 (2015)

Influence of V-pits on the efficiency droop in InGaN/GaN quantum wells

Jaekyun Kim, Yong-Hee Cho, Dong-Su Ko, Xiang-Shu Li, Jung-Yeon Won, Eunha Lee, Seoung-Hwan Park, Jun-Youn Kim, and Sungjin Kim
Opt. Express 22(S3) A857-A866 (2014)

Cited By

Optica participates in Crossref's Cited-By Linking service. Citing articles from Optica Publishing Group journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (4)

Fig. 1
Fig. 1 Edge PL spectra of AlGaN MQWs samples A1 (a) and C1 (b) measured at 20 K temperature under several excitation power densities below and above the threshold for stimulated emission. The threshold was equal to 170 kW/cm2 and 970 kW/cm2 for samples A1 and C1, respectively. The spectra were normalized and shifted for clarity. The vertical line indicates the peak positions of spontaneous luminescence bands.
Fig. 2
Fig. 2 Temperature dependences of PL band peak position shift relative to the position at 8 K in AlGaN MQWs (points) for the samples listed in Table 1. Solid lines show the best fit using a simple model of carrier (exciton) hopping through localized states.
Fig. 3
Fig. 3 Normalized PL efficiency dependences on excitation power density in AlGaN MQWs with different localization strengths (indicated) at 300 K (a) and 8 K (b).
Fig. 4
Fig. 4 Ratio of thresholds for stimulated emission and droop onset as a function of the ratio of thermal energy to dispersion of potential fluctuations for 6 different samples at various temperatures. The solid line indicates the ratio between stimulated emission threshold and droop onset equal to 1.

Tables (1)

Tables Icon

Table 1 The structure details of the samples under study.

Equations (1)

Equations on this page are rendered with MathJax. Learn more.

E peak ( T )= E g ( 0 ) α T 2 β+T σ 2 k B T .
Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved