The influence of V-defects, leakage, and random alloy fluctuations on the carrier transport in red InGaN MQW LEDs

Journal Article · Tue Jul 01 00:00:00 EDT 2025 · Applied Physics Reviews

DOI:https://doi.org/10.1063/5.0261821· OSTI ID:3023039

Huang, Huai-Chin ^[1]; Chen, Shih-Min ^[1]; Weisbuch, Claude ^[2]; Speck, James S. ^[3]; Wu, Yuh-Renn ^[1]

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1. National Taiwan Univ., Taipei (Taiwan)
2. Ecole Polytechnique, Palaiseau (France)
3. Univ. of California, Santa Barbara, CA (United States)

Red InGaN-based light-emitting diodes (LEDs) exhibit lower internal quantum efficiencies than violet, blue, and green InGaN LEDs due to a reduction in radiative recombination rates relative to non-radiative recombination rates as the Indium composition increases. Additionally, the larger polarization and band offset barriers between high indium content InGaN quantum wells and GaN quantum barriers increase the forward voltage. In blue and green LEDs, random alloy fluctuations and V-defects play a key role in reducing the forward voltage. When V-defects are present, either naturally or intentionally introduced, they create an alternative path for carrier injection into the MQWs through the V-defect sidewalls. This injection mechanism explains the turn-on voltages of green LEDs. However, in InGaN red LEDs, these two phenomena do not reduce the forward voltage as effectively as in blue and green LEDs, and consequently, the computed forward voltage remains significantly higher than the measured one. Furthermore, currents are observed at low voltages before the turn-on voltage (V<ℏω/e=2.0 V) of red LEDs. To address this, we introduce dislocation-induced tail states in the modeling, suggesting that leakage current through these states may play a significant role both below and at turn-on voltages. The simulation also indicates that leakage carriers below turn-on accumulate, partially diffuse in the QWs, screen the polarization-induced barrier in the low injection regime, and further reduce the forward voltage. Despite these beneficial effects, a drawback of dislocation-induced tail states is the enhanced nonradiative recombination in the dislocation line region. This study provides a detailed analysis of device injection physics in InGaN QW red LEDs and outlines potential optimization strategies.

• Research Organization: Univ. of California, Santa Barbara, CA (United States)
• Sponsoring Organization: National Science Foundation; USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: EE0009691
• Other Award/Contract Number: 112-2221-E-002-215-MY3; 113-2124-M-002-013-MY3; 113M7056; DMS-1839077; 601952; 1027114; 113-2640-E-002-005; 112-2221-E-002-214-MY3
• OSTI ID: 3023039
• Journal Information: Applied Physics Reviews, Journal Name: Applied Physics Reviews Journal Issue: 3 Vol. 12; ISSN 1931-9401
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
Charge recombination
Crystallographic defects
Current-voltage characteristic
Electrical properties and parameters
Electronic band structure
Light emitting diodes
Materials properties
Potential energy barrier
Quantum wells
Semiconductor materials