Article
Physics, Applied
Saulius Marcinkevicius, Rinat Yapparov, Yi Chao Chow, Cheyenne Lynsky, Shuji Nakamura, Steven P. DenBaars, James S. Speck
Summary: Time-resolved and quasi-cw photoluminescence spectroscopy was used to measure the internal quantum efficiency of c-plane InGaN single quantum wells. The low temperature IQE was found to be 100%, with IQE over 60% for QWs emitting in green and green-yellow spectral regions at 300 K. Extended defects like threading dislocations and V-defects did not significantly affect carrier recombination.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Li Liu, Qingqing Feng, Yu Zhang, Xiaolu Zhu, Lanli Chen, Zhihua Xiong
Summary: Improving the luminescence efficiency of long wavelength InGaN-based LEDs is a challenging task, and strain-induced piezoelectric effect has been shown to be an effective measure. Reduction of valence band offset at InGaN/GaN heterointerfaces significantly improves hole injection. Tensile strain in the GaN film on a silicon substrate increases the overlap of electron and hole wave functions, leading to enhanced efficiency. Control of the strain-induced piezoelectric polarisation of the InGaN quantum well layer further improves the internal quantum efficiency.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Yu Zhang, Xiaolu Zhu, Lei Ao, Zhihua Xiong
Summary: The indium gallium nitride (InGaN)-based micro-LEDs hold great promise for future displays, but the low efficiency of InGaN-based red LEDs is a major obstacle for their development. This study investigates the effects of substrate-induced strain on the behavior of In atoms on GaN surfaces using first-principles calculations. The results show that applying slight tensile strain enhances In adsorption and promotes In incorporation in the GaN surface. Additionally, using substrates with larger lattice constants can stabilize the InGaN system and suppress phase separation.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
Sourav Roy, S. M. Tasmeeh Ahsan, Nibir Mondol, Md Mahmudul Hasan, Diponkar Kundu, Shakil Mahmud Boby, Mehedi Hassan, Md Sanwar Hossain, Md Rasidul Islam, Md Biplob Hossain, Shuvagoto Dhar, Md Amzad Hossain
Summary: Semipolar InGaN-based blue laser diodes (LDs) have gained significant attention in the solid-state lighting industry due to their reduction in internal polarization field and related quantum-confined stark effect. However, a comparative study among different semipolar-oriented InGaN blue LDs in terms of energy band gap, optical emission profile, power output, and forward bias response is currently unattainable. This study aims to investigate the impact of internal polarization field on the optoelectronic parameters of InGaN blue LDs along different crystal orientations and demonstrates the superiority of the (1122)-oriented InGaN blue LD for high-speed visible-light communications.
RESULTS IN PHYSICS
(2022)
Article
Optics
Yang Mei, Yan-hui Chen, Lei-ying Ying, Ai-qin Tian, Guo-en Weng, Long Hao, Jian-ping Liu, Bao-ping Zhang
Summary: Dual-wavelength switchable emission has been achieved in InGaN QD micro-cavity light-emitting diodes. By modulating the injected current levels, the device can switch between two distinct cavity modes in the green spectral range. The microcavity effect enables high spectral purity. This study provides important guidelines for controllable dual-wavelength switchable operation in nitride-based light-emitting devices.
Article
Materials Science, Multidisciplinary
Yufei Hou, Degang Zhao, Feng Liang, Jing Yang, Ping Chen, Zongshun Liu
Summary: The injection of holes plays a crucial role in the performance of InGaN-based green laser diodes (LDs). A new structure with InGaN hole reservoir layer (HRL) inserted between the last quantum barrier and the upper waveguide is proposed to enhance hole injection, resulting in significantly increased hole injection current and improved device properties. Adjusting the thickness and In composition of the HRL can further optimize the performance of LDs, with better results observed when the HRL has a low-In content and a thickness of around 11 nm.
Article
Optics
Yuhao Ben, Feng Liang, Degang Zhao, Jing Yang, Zongshun Liu, Ping Chen
Summary: The use of InGaN instead of GaN as a quantum barrier layer can significantly reduce the threshold current of blue laser diodes, but the improvement in slope efficiency is limited due to an increase in leakage current. However, experimental results show a significant increase in slope efficiency by 34% in fabricated LDs using InGaN quantum barrier layers compared to those using GaN quantum barrier layers.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Liwen Cheng, Zhenwei Li, Jiayi Zhang, Xingyu Lin, Da Yang, Haitao Chen, Shudong Wu, Shun Yao
Summary: An InGaN laser diode with InGaN-GaN-InGaN delta barriers demonstrates lower turn-on current, higher laser power, and higher slope efficiency compared to those with InGaN or conventional GaN barriers. These improvements are attributed to modified energy bands that enhance carrier injection within the active region.
Article
Physics, Applied
Yi Chao Chow, Tanay Tak, Feng Wu, Jacob Ewing, Shuji Nakamura, Steven P. Denbaars, Yuh-Renn Wu, Claude Weisbuch, James S. Speck
Summary: We investigate the unexpected high-energy electroluminescence (EL) peaks observed in long-wavelength InGaN light-emitting diodes (LEDs) and identify two high-energy emission peaks. These peaks are attributed to transitions involving excited states and V-defect sidewalls, and their origins and influencing factors are examined.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Shengjun Zhou, Zehong Wan, Yu Lei, Bin Tang, Guoyi Tao, Peng Du, Xiaoyu Zhao
Summary: This study proposes the use of InGaN quantum wells with gradually varying indium content to enhance the performance of GaN-based green LEDs. Experimental results demonstrate that green LEDs with gradually varying indium content exhibit higher light output power and lower efficiency droop.
Article
Physics, Applied
Saulius Marcinkevicius, Jacob Ewing, Rinat Yapparov, Feng Wu, Shuji Nakamura, James S. Speck
Summary: Hole injection through V-defect sidewalls into all quantum wells can increase the efficiency of long wavelength GaN light emitting diodes, allowing for population of all wells in a multiple QW structure.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Pradip Dalapati, Kosuke Yamamoto, Takashi Egawa, Makoto Miyoshi
Summary: The degradation characteristics of InGaN/GaN multiple quantum well (MQW) photodetectors (PDs) under 100 and 200 mA current stress for 480 hours were investigated. The results showed that the luminescence intensity, short circuit current density, and open circuit voltage decrease significantly, while the leakage current increases intensely under constant current stress. Additionally, the photocurrent spectroscopy results revealed changes in the peak value of relative external quantum efficiency (EQE) under different stress currents.
Article
Chemistry, Multidisciplinary
Chaoqiang Zhang, Ke Gao, Fei Wang, Zhiming Chen, Philip Shields, Sean Lee, Yanqin Wang, Dongyan Zhang, Hongwei Liu, Pingjuan Niu
Summary: This paper investigates the edge strain relaxation of InGaN/GaN MQW micro-pillars. The results show a significant peak wavelength shift between micro-pillar arrays caused by a high range of strain relaxation. Raman spectrum observation and finite element method simulation provide effective verification of the strain relaxation analysis, offering references for the design and analysis of small-size micro-LED devices.
APPLIED SCIENCES-BASEL
(2022)
Review
Materials Science, Multidisciplinary
Zhaojun Liu, Byung-Ryool Hyun, Yujia Sheng, Chun-Jung Lin, Mengyuan Changhu, Yonghong Lin, Chih-Hsiang Ho, Jr-Hau He, Hao-Chung Kuo
Summary: Micro-light-emitting diodes (Micro-LEDs) based on gallium nitride (GaN) materials offer versatile platforms for various applications, including displays, data communication tools, photodetectors, and sensors. By combining with quantum dots, Micro-LEDs can achieve efficient full-color displays and high-speed visible light communications.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Optics
Shuyuan Zhang, Wei Liu, Jie Zhang, Hengyan Zhao, Zeyu Liu, Zhangbo Hu
Summary: The influence of the position of the InGaN layer on the electroluminescence properties of red InGaN/GaN single quantum well light-emitting diodes was numerically investigated. It was found that as the InGaN well shifts from the P-region to the N-region, the EL intensity decreases, and the spectrum red-shifts. The reduction in EL intensity is attributed to the enhanced injection efficiency of holes and weakened injection efficiency of electrons, resulting in a decrease in the total amount of carriers.
JOURNAL OF LUMINESCENCE
(2022)
