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Chen J, Liu J, Huang Y, Liu R, Dai Y, Tang L, Chen Z, Sun X, Liu C, Zhang S, Sun Q, Feng M, Xu Q, Yang H. Hillock Related Degradation Mechanism for AlGaN-Based UVC LEDs. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13091562. [PMID: 37177107 PMCID: PMC10180975 DOI: 10.3390/nano13091562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
Heteroepitaxial growth of high Al-content AlGaN often results in a high density of threading dislocations and surface hexagonal hillocks, which degrade the performance and reliability of AlGaN-based UVC light emitting diodes (LEDs). In this study, the degradation mechanism and impurity/defect behavior of UVC LEDs in relation to the hexagonal hillocks have been studied in detail. It was found that the early degradation of UVC LEDs is primarily caused by electron leakage. The prominent contribution of the hillock edges to the electron leakage is unambiguously evidenced by the transmission electron microscopy measurements, time-of-flight secondary ion mass spectrometry, and conductive atomic force microscopy. Dislocations bunching and segregation of impurities, including C, O, and Si, at the hillock edges are clearly observed, which facilitate the trap-assisted carrier tunneling in the multiple quantum wells and subsequent recombination in the p-AlGaN. This work sheds light on one possible degradation mechanism of AlGaN-based UVC LEDs.
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Affiliation(s)
- Juntong Chen
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Jianxun Liu
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
- Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528000, China
| | - Yingnan Huang
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Ruisen Liu
- Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528000, China
| | - Yayu Dai
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Leming Tang
- Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528000, China
| | - Zheng Chen
- Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528000, China
| | - Xiujian Sun
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Chenshu Liu
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Shuming Zhang
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
- Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528000, China
| | - Qian Sun
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
- Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528000, China
| | - Meixin Feng
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
- Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528000, China
| | - Qiming Xu
- GuSu Laboratory of Materials, Suzhou 215123, China
| | - Hui Yang
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
- GuSu Laboratory of Materials, Suzhou 215123, China
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Li D, Liu S, Qian Z, Liu Q, Zhou K, Liu D, Sheng S, Sheng B, Liu F, Chen Z, Wang P, Wang T, Rong X, Tao R, Kang J, Chen F, Kang J, Yuan Y, Wang Q, Sun M, Ge W, Shen B, Tian P, Wang X. Deep-Ultraviolet Micro-LEDs Exhibiting High Output Power and High Modulation Bandwidth Simultaneously. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109765. [PMID: 35297518 DOI: 10.1002/adma.202109765] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/20/2022] [Indexed: 06/14/2023]
Abstract
Deep-ultraviolet (DUV) solar-blind communication (SBC) shows distinct advantages of non-line-of-sight propagation and background noise negligibility over conventional visible-light communication. AlGaN-based DUV micro-light-emitting diodes (µ-LEDs) are an excellent candidate for a DUV-SBC light source due to their small size, low power consumption, and high modulation bandwidth. A long-haul DUV-SBC system requires the light source exhibiting high output power, high modulation bandwidth, and high rate, simultaneously. Such a device is rarely reported. A parallel-arrayed planar (PAP) approach is here proposed to satisfy those requirements. By reducing the dimensions of the active emission mesa to micrometer scale, DUV µ-LEDs with ultrahigh power density are created due to their homogeneous injection current and enhanced planar isotropic light emission. Interconnected PAP µ-LEDs with a diameter of 25 µm are produced. This device has an output power of 83.5 mW with a density of 405 W cm-2 at 230 mA, a wall-plug efficiency (WPE) of 4.7% at 155 mA, and a high -3 dB modulation bandwidth of 380 MHz. The remarkable high output power and efficiency make those devices a reliable platform to develop high-modulation-bandwidth wireless communication and to meet the requirements for bio-elimination.
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Affiliation(s)
- Duo Li
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Shangfeng Liu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Zeyuan Qian
- School of Information Science and Technology, Fudan University, Shanghai, 200438, China
| | - Quanfeng Liu
- Dongguan Sino Crystal Semiconductor Co., Ltd., Dongguan, 523500, China
| | - Kang Zhou
- Dongguan Sino Crystal Semiconductor Co., Ltd., Dongguan, 523500, China
| | - Dandan Liu
- Dongguan Sino Crystal Semiconductor Co., Ltd., Dongguan, 523500, China
| | - Shanshan Sheng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Bowen Sheng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Fang Liu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Zhaoying Chen
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Ping Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Tao Wang
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
| | - Xin Rong
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Renchun Tao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Jianbin Kang
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200, China
| | - Feiliang Chen
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Junjie Kang
- Songshan Lake Materials Laboratory, Dongguan, 523808, China
| | - Ye Yuan
- Songshan Lake Materials Laboratory, Dongguan, 523808, China
| | - Qi Wang
- Dongguan Institute of Opto-Electronics Peking University, Dongguan, 523808, China
| | - Ming Sun
- Dongguan Sino Crystal Semiconductor Co., Ltd., Dongguan, 523500, China
| | - Weikun Ge
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Bo Shen
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing, 100871, China
| | - Pengfei Tian
- School of Information Science and Technology, Fudan University, Shanghai, 200438, China
| | - Xinqiang Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Dongguan Institute of Opto-Electronics Peking University, Dongguan, 523808, China
- Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing, 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu, 226010, China
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Lu S, Zheng T, Jiang K, Sun X, Li D, Chen H, Li J, Zhou Y, Cai D, Li S, Lin W, Kang J. Regulating the valence level arrangement of high-Al-content AlGaN quantum wells using additional potentials with Mg doping. Phys Chem Chem Phys 2022; 24:5529-5538. [PMID: 35172325 DOI: 10.1039/d1cp04303j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Quantum states and arrangement of valence levels determine most of the electronic and optical properties of semiconductors. Since the crystal field split-off hole (CH) band is the top valence band in high-Al-content AlGaN, TM-polarized optical anisotropy has become the limiting factor for efficient deep-ultraviolet (DUV) light emission. Additional potentials, including on-site Coulomb interaction and orbital state coupling induced by magnesium (Mg) doping, are proposed in this work to regulate the valence level arrangement of AlN/Al0.75Ga0.25N quantum wells (QWs). Diverse responses of valence quantum states |pi〉 (i = x, y, or z) of AlGaN to additional potentials due to different configurations and interactions of orbitals revealed by first-principles simulations are understood in terms of the linear combination of atomic orbital states. A positive charge and large Mg dopant in QWs introduce an additional Coulomb potential and modulate the orbital coupling distance. For the CH band (pz orbital), the Mg-induced Coulomb potential compensates the orbital coupling energy. Meanwhile, the heavy/light hole (HH/LH) bands (px and py orbitals) are elevated by the Mg-induced Coulomb potential. Consequently, HH/LH energy levels are relatively shifted upward and replace the CH level to be the top of the valence band. The inversion of optical anisotropy and enhancement of TE-polarized emission are further confirmed experimentally via spectroscopic ellipsometry.
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Affiliation(s)
- Shiqiang Lu
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Tongchang Zheng
- Department of Physics, School of Science, Jimei University, Xiamen 361021, China
| | - Ke Jiang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Dongnanhu Road No. 3888, Changchun 130033, China
| | - Xiaojuan Sun
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Dongnanhu Road No. 3888, Changchun 130033, China
| | - Dabing Li
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Dongnanhu Road No. 3888, Changchun 130033, China
| | - Hangyang Chen
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Jinchai Li
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Yinghui Zhou
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Duanjun Cai
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Shuping Li
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Wei Lin
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Junyong Kang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
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Lu S, Jiang X, Wang Y, Huang K, Gao N, Cai D, Zhou Y, Yang CC, Kang J, Zhang R. Enhancing deep-UV emission at 234 nm by introducing a truncated pyramid AlN/GaN nanostructure with fine-tuned multiple facets. NANOSCALE 2022; 14:653-662. [PMID: 35018953 DOI: 10.1039/d1nr06188g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The external quantum efficiency of a high-Al content (>0.6) AlGaN deep-ultraviolet (DUV) light-emitting diode is typically below 1% in the sub-250 nm wavelength range. One of the main reasons for this low efficiency is the fundamental properties of high-Al content AlGaN comprising the transverse-magnetic (TM)-dominant emission and low light extraction due to the total internal reflection (TIR). This work demonstrates a truncated pyramid nanostructure with fine-tuned multiple facets in an (AlN)8/(GaN)2 digital alloy to achieve highly efficient DUV emission at 234 nm. By applying nanoimprint lithography, dry and wet etching, a hexagonal truncated pyramid nanohole structure is fabricated featuring multiple crystal facets of (0001), (10-13), and (20-21) planes. These fine-tuned multiple facets act as reflecting mirrors that can effectively modulate the light propagation and extraction patterns to overcome the TIR via multiple reflections and enhanced scattering. Consequently, significant light extraction enhancements of 5.6 times and 1.1 times for TM and transverse-electric emissions are achieved in the truncated pyramid nanohole structure, respectively. The total luminous intensity of this unique nanostructure is greatly increased by 191% compared to that of a conventional planar structure. The truncated pyramid AlN/GaN nanostructure with fine-tuned multiple facets used in this work provides a promising approach for realizing highly efficient sub-250 nm DUV light-emitting devices.
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Affiliation(s)
- Shiqiang Lu
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Xinjun Jiang
- Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Yaozeng Wang
- Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Kai Huang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Na Gao
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Duanjun Cai
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Yinghui Zhou
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - C C Yang
- Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Junyong Kang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Rong Zhang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen 361005, China.
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Lu S, Luo Z, Li J, Lin W, Chen H, Liu D, Cai D, Huang K, Gao N, Zhou Y, Li S, Kang J. Role of Strain-Induced Microscale Compositional Pulling on Optical Properties of High Al Content AlGaN Quantum Wells for Deep-Ultraviolet LED. NANOSCALE RESEARCH LETTERS 2022; 17:13. [PMID: 35032237 PMCID: PMC8760570 DOI: 10.1186/s11671-022-03652-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
A systematic study was carried out for strain-induced microscale compositional pulling effect on the structural and optical properties of high Al content AlGaN multiple quantum wells (MQWs). Investigations reveal that a large tensile strain is introduced during the epitaxial growth of AlGaN MQWs, due to the grain boundary formation, coalescence and growth. The presence of this tensile strain results in the microscale inhomogeneous compositional pulling and Ga segregation, which is further confirmed by the lower formation enthalpy of Ga atom than Al atom on AlGaN slab using first principle simulations. The strain-induced microscale compositional pulling leads to an asymmetrical feature of emission spectra and local variation in emission energy of AlGaN MQWs. Because of a stronger three-dimensional carrier localization, the area of Ga segregation shows a higher emission efficiency compared with the intrinsic area of MQWs, which is benefit for fabricating efficient AlGaN-based deep-ultraviolet light-emitting diode.
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Affiliation(s)
- Shiqiang Lu
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Zongyan Luo
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Jinchai Li
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China.
| | - Wei Lin
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Hangyang Chen
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China.
| | - Dayi Liu
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Duanjun Cai
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Kai Huang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Na Gao
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Yinghui Zhou
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Shuping Li
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Junyong Kang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
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Li J, Gao N, Cai D, Lin W, Huang K, Li S, Kang J. Multiple fields manipulation on nitride material structures in ultraviolet light-emitting diodes. LIGHT, SCIENCE & APPLICATIONS 2021; 10:129. [PMID: 34150202 PMCID: PMC8206881 DOI: 10.1038/s41377-021-00563-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/25/2021] [Accepted: 05/24/2021] [Indexed: 05/22/2023]
Abstract
As demonstrated during the COVID-19 pandemic, advanced deep ultraviolet (DUV) light sources (200-280 nm), such as AlGaN-based light-emitting diodes (LEDs) show excellence in preventing virus transmission, which further reveals their wide applications from biological, environmental, industrial to medical. However, the relatively low external quantum efficiencies (mostly lower than 10%) strongly restrict their wider or even potential applications, which have been known related to the intrinsic properties of high Al-content AlGaN semiconductor materials and especially their quantum structures. Here, we review recent progress in the development of novel concepts and techniques in AlGaN-based LEDs and summarize the multiple physical fields as a toolkit for effectively controlling and tailoring the crucial properties of nitride quantum structures. In addition, we describe the key challenges for further increasing the efficiency of DUV LEDs and provide an outlook for future developments.
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Affiliation(s)
- Jinchai Li
- Engineering Research Center of Micro-nano Optoelectronic Materials and Devices, Ministry of Education, Fujian Key Laboratory of Semiconductor Materials and Applications, CI center for OSED, College of Physical Science and Technology, Xiamen University, 361005 Xiamen, China
| | - Na Gao
- Engineering Research Center of Micro-nano Optoelectronic Materials and Devices, Ministry of Education, Fujian Key Laboratory of Semiconductor Materials and Applications, CI center for OSED, College of Physical Science and Technology, Xiamen University, 361005 Xiamen, China
| | - Duanjun Cai
- Engineering Research Center of Micro-nano Optoelectronic Materials and Devices, Ministry of Education, Fujian Key Laboratory of Semiconductor Materials and Applications, CI center for OSED, College of Physical Science and Technology, Xiamen University, 361005 Xiamen, China
| | - Wei Lin
- Engineering Research Center of Micro-nano Optoelectronic Materials and Devices, Ministry of Education, Fujian Key Laboratory of Semiconductor Materials and Applications, CI center for OSED, College of Physical Science and Technology, Xiamen University, 361005 Xiamen, China
| | - Kai Huang
- Engineering Research Center of Micro-nano Optoelectronic Materials and Devices, Ministry of Education, Fujian Key Laboratory of Semiconductor Materials and Applications, CI center for OSED, College of Physical Science and Technology, Xiamen University, 361005 Xiamen, China
| | - Shuping Li
- Engineering Research Center of Micro-nano Optoelectronic Materials and Devices, Ministry of Education, Fujian Key Laboratory of Semiconductor Materials and Applications, CI center for OSED, College of Physical Science and Technology, Xiamen University, 361005 Xiamen, China
| | - Junyong Kang
- Engineering Research Center of Micro-nano Optoelectronic Materials and Devices, Ministry of Education, Fujian Key Laboratory of Semiconductor Materials and Applications, CI center for OSED, College of Physical Science and Technology, Xiamen University, 361005 Xiamen, China
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Lu S, Li J, Huang K, Liu G, Zhou Y, Cai D, Zhang R, Kang J. Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density. NANOSCALE RESEARCH LETTERS 2021; 16:99. [PMID: 34081221 PMCID: PMC8175512 DOI: 10.1186/s11671-021-03557-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/24/2021] [Indexed: 05/14/2023]
Abstract
Here we report a comprehensive numerical study for the operating behavior and physical mechanism of nitride micro-light-emitting-diode (micro-LED) at low current density. Analysis for the polarization effect shows that micro-LED suffers a severer quantum-confined Stark effect at low current density, which poses challenges for improving efficiency and realizing stable full-color emission. Carrier transport and matching are analyzed to determine the best operating conditions and optimize the structure design of micro-LED at low current density. It is shown that less quantum well number in the active region enhances carrier matching and radiative recombination rate, leading to higher quantum efficiency and output power. Effectiveness of the electron blocking layer (EBL) for micro-LED is discussed. By removing the EBL, the electron confinement and hole injection are found to be improved simultaneously, hence the emission of micro-LED is enhanced significantly at low current density. The recombination processes regarding Auger and Shockley-Read-Hall are investigated, and the sensitivity to defect is highlighted for micro-LED at low current density.Synopsis: The polarization-induced QCSE, the carrier transport and matching, and recombination processes of InGaN micro-LEDs operating at low current density are numerically investigated. Based on the understanding of these device behaviors and mechanisms, specifically designed epitaxial structures including two QWs, highly doped or without EBL and p-GaN with high hole concentration for the efficient micro-LED emissive display are proposed. The sensitivity to defect density is also highlighted for micro-LED.
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Affiliation(s)
- Shiqiang Lu
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Jinchai Li
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China.
- Future Display Institute of Xiamen, Xiamen, 361005, People's Republic of China.
| | - Kai Huang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China
- Future Display Institute of Xiamen, Xiamen, 361005, People's Republic of China
| | - Guozhen Liu
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Yinghui Zhou
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Duanjun Cai
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China.
| | - Rong Zhang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China
- Future Display Institute of Xiamen, Xiamen, 361005, People's Republic of China
| | - Junyong Kang
- Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China.
- Future Display Institute of Xiamen, Xiamen, 361005, People's Republic of China.
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