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Hsu YH, Lin XD, Lin YH, Wuu DS, Horng RH. Performance comparison of flip-chip blue-light microLEDs with various passivation. DISCOVER NANO 2024; 19:129. [PMID: 39150592 PMCID: PMC11329445 DOI: 10.1186/s11671-024-04078-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 08/06/2024] [Indexed: 08/17/2024]
Abstract
In this study, arrays of μLEDs in four different sizes (5 × 5 μm2, 10 × 10 μm2, 25 × 25 μm2, 50 × 50 μm2) were fabricated using a flip-chip bonding process. Two passivation processes were investigated with one involving a single layer of SiO2 deposited using plasma-enhanced chemical vapor deposition (PECVD) and the other incorporating Al2O3 deposited by atomic layer deposition (ALD) beneath the SiO2 layer. Owing to superior coverage and protection, the double-layers passivation process resulted in a three-order lower leakage current of μLEDs in the 5 μm chip-sized μLED arrays. Furthermore, higher light output power of μLEDs was observed in each chip-sized μLED array with double layers passivation. Particularly, the highest EQE value 21.9% of μLEDs array with 5 μm × 5 μm chip size was achieved with the double-layers passivation. The EQE value of μLEDs array was improved by 4.4 times by introducing the double-layers passivation as compared with that of μLEDs array with single layer passivation. Finally, more uniform light emission patterns were observed in the μLEDs with 5 μm × 5 μm chip size fabricated by double-layer passivation process using ImageJ software.
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Affiliation(s)
- Yu-Hsuan Hsu
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
- Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Xin-Dai Lin
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Yi-Hsin Lin
- Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Dong-Sing Wuu
- Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou, 54561, Taiwan, ROC
| | - Ray-Hua Horng
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC.
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2
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Lin SH, Lo YY, Hsu YH, Lin CC, Zan HW, Lin YH, Wuu DS, Hsiao CL, Horng RH. Study on different isolation technology on the performance of blue micro-LEDs array applications. DISCOVER NANO 2024; 19:102. [PMID: 38869646 DOI: 10.1186/s11671-024-04047-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Accepted: 06/10/2024] [Indexed: 06/14/2024]
Abstract
In this study, a 3 × 3 blue micro-LED array with a pixel size of 10 × 10 μm2 and a pitch of 15 μm was fabricated on an epilayer grown on a sapphire substrate using metalorganic chemical vapor deposition technology. The fabrication process involved photolithography, wet and dry etching, E-beam evaporation, and ion implantation technology. Arsenic multi-energy implantation was utilized to replace the mesa etching for electrical isolation, where the implantation depth increased with the average energy. Different ion depth profiles had varying effects on electrical properties, such as forward current and leakage currents, potentially causing damage to the n-GaN layer and increasing the series resistance of the LEDs. As the implantation depth increased, the light output power and peak external quantum efficiency of the LEDs also increased, improving from 5.33 to 9.82%. However, the efficiency droop also increased from 46.3 to 48.6%.
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Affiliation(s)
- Shao-Hua Lin
- Institute of Electrics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Yu-Yun Lo
- Department of Photonis, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Yu-Hsuan Hsu
- Department of Photonis, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Chien-Chung Lin
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan, ROC
| | - Hsiao-Wen Zan
- Department of Photonis, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Yi-Hsin Lin
- Department of Photonis, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC
| | - Dong-Sing Wuu
- Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou, 54561, Taiwan, ROC
| | - Ching-Lien Hsiao
- Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, 581 83, Linköping, Sweden
| | - Ray-Hua Horng
- Institute of Electrics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC.
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Wong MS, Trageser ES, Zhang H, Chang HM, Gee S, Tak T, Gandrothula S, Lee C, Speck JS, Nakamura S, Cohen DA, DenBaars SP. III-nitride m-plane violet narrow ridge edge-emitting laser diodes with sidewall passivation using atomic layer deposition. OPTICS EXPRESS 2024; 32:20483-20490. [PMID: 38859429 DOI: 10.1364/oe.520339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 05/06/2024] [Indexed: 06/12/2024]
Abstract
A novel deep-ridge laser structure with atomic-layer deposition (ALD) sidewall passivation was proposed that enhances the optical characteristics of 8-µm ridge width III-nitride violet lasers on freestanding m-plane GaN substrates. The internal loss was determined using the variable stripe length method, where the laser structure with ALD sidewall passivation showed lower internal loss compared to the conventional shallow-ridge laser design. ALD sidewall passivation plays a critical role in device improvements; compared to the lasers without ALD sidewall passivation, the lasers with ALD sidewall passivation yield improved optoelectrical performance and longer lifetime under continuous-wave operation at high current density. This work demonstrates the importance of ALD sidewall passivation to laser performance, which enables high energy efficiency.
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Hsiao FH, Lee TY, Miao WC, Pai YH, Iida D, Lin CL, Chen FC, Chow CW, Lin CC, Horng RH, He JH, Ohkawa K, Hong YH, Chang CY, Kuo HC. Investigations on the high performance of InGaN red micro-LEDs with single quantum well for visible light communication applications. DISCOVER NANO 2023; 18:95. [PMID: 37498403 PMCID: PMC10374497 DOI: 10.1186/s11671-023-03871-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/07/2023] [Indexed: 07/28/2023]
Abstract
In this study, we have demonstrated the potential of InGaN-based red micro-LEDs with single quantum well (SQW) structure for visible light communication applications. Our findings indicate the SQW sample has a better crystal quality, with high-purity emission, a narrower full width at half maximum, and higher internal quantum efficiency, compared to InGaN red micro-LED with a double quantum wells (DQWs) structure. The InGaN red micro-LED with SQW structure exhibits a higher maximum external quantum efficiency of 5.95% and experiences less blueshift as the current density increases when compared to the DQWs device. Furthermore, the SQW device has a superior modulation bandwidth of 424 MHz with a data transmission rate of 800 Mbit/s at an injection current density of 2000 A/cm2. These results demonstrate that InGaN-based SQW red micro-LEDs hold great promise for realizing full-color micro-display and visible light communication applications.
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Affiliation(s)
- Fu-He Hsiao
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Tzu-Yi Lee
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Wen-Chien Miao
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Yi-Hua Pai
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Daisuke Iida
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955 6900, Saudi Arabia
| | - Chun-Liang Lin
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Fang-Chung Chen
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Chi-Wai Chow
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Chien-Chung Lin
- Department of Electrical Engineering, National Taiwan University, Taipei, 10639, Taiwan
| | - Ray-Hua Horng
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Jr-Hau He
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong Special Administrative Region, China
| | - Kazuhiro Ohkawa
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955 6900, Saudi Arabia
| | - Yu-Heng Hong
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan.
| | - Chiao-Yun Chang
- Department of Electrical Engineering, National Taiwan Ocean University, Keelung, 202301, Taiwan.
| | - Hao-Chung Kuo
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan.
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
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Yee CK, Lin JM, Wu MJ, Cheng HT, Huang CW, Lee CA, Lin KH, Wu CC, Wu CH. High uniformity red µ-LED array with a current efficiency of 2.6 cd/A and ns-level response time. OPTICS LETTERS 2023; 48:2933-2936. [PMID: 37262247 DOI: 10.1364/ol.490016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 04/28/2023] [Indexed: 06/03/2023]
Abstract
This paper demonstrates an AlGaInP-based 620-nm red micro-light-emitting-diode (µ-LED) array and studies the enhancement effect of the surface treatments using (NH4)2Sx solutions by comparing the characteristics of µ-LED arrays with and without the (NH4)2Sx treatment. Furthermore, our µ-LED array demonstrates a measurement of the current efficiency (2.6 cd/A), which improves the light output uniformity. Also, we apply a setup for measuring the response time at the fast ns-level to analyze the effect of passivation in AlGaInP-based µ-LED arrays.
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Hsiao FH, Miao WC, Hong YH, Chiang H, Ho IH, Liang KB, Iida D, Lin CL, Ahn H, Ohkawa K, Chang CY, Kuo HC. Structural and optical analyses for InGaN-based red micro-LED. DISCOVER NANO 2023; 18:77. [PMID: 37382747 DOI: 10.1186/s11671-023-03853-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/04/2023] [Indexed: 06/30/2023]
Abstract
This study presents a comprehensive analysis of the structural and optical properties of an InGaN-based red micro-LED with a high density of V-shaped pits, offering insights for enhancing emission efficiency. The presence of V-shaped pits is considered advantageous in reducing non-radiative recombination. Furthermore, to systematically investigate the properties of localized states, we conducted temperature-dependent photoluminescence (PL). The results of PL measurements indicate that deep localization in the red double quantum wells can limit carrier escape and improve radiation efficiency. Through a detailed analysis of these results, we extensively investigated the direct impact of epitaxial growth on the efficiency of InGaN red micro-LEDs, thereby laying the foundation for improving efficiency in InGaN-based red micro-LEDs.
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Affiliation(s)
- Fu-He Hsiao
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Wen-Chien Miao
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Yu-Heng Hong
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan
| | - Hsin Chiang
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - I-Hung Ho
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Kai-Bo Liang
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Daisuke Iida
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955 6900, Saudi Arabia
| | - Chun-Liang Lin
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Hyeyoung Ahn
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Kazuhiro Ohkawa
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955 6900, Saudi Arabia
| | - Chiao-Yun Chang
- Department of Electrical Engineering, National Taiwan Ocean University, Keelung, 202301, Taiwan.
| | - Hao-Chung Kuo
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan.
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
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James Singh K, Huang WT, Hsiao FH, Miao WC, Lee TY, Pai YH, Kuo HC. Recent Advances in Micro-LEDs Having Yellow-Green to Red Emission Wavelengths for Visible Light Communications. MICROMACHINES 2023; 14:mi14020478. [PMID: 36838178 PMCID: PMC9960147 DOI: 10.3390/mi14020478] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/14/2023] [Accepted: 02/17/2023] [Indexed: 06/01/2023]
Abstract
Visible light communication (VLC), which will primarily support high-speed internet connectivity in the contemporary world, has progressively come to be recognized as a significant alternative and reinforcement in the wireless communication area. VLC has become more popular recently because of its many advantages over conventional radio frequencies, including a higher transmission rate, high bandwidth, low power consumption, fewer health risks, and reduced interference. Due to its high-bandwidth characteristics and potential to be used for both illumination and communications, micro-light-emitting diodes (micro-LEDs) have drawn a lot of attention for their use in VLC applications. In this review, a detailed overview of micro-LEDs that have long emission wavelengths for VLC is presented, along with their related challenges and future prospects. The VLC performance of micro-LEDs is influenced by a number of factors, including the quantum-confined Stark effect (QCSE), size-dependent effect, and droop effect, which are discussed in the following sections. When these elements are combined, it has a major impact on the performance of micro-LEDs in terms of their modulation bandwidth, wavelength shift, full-width at half maximum (FWHM), light output power, and efficiency. The possible challenges faced in the use of micro-LEDs were analyzed through a simulation conducted using Crosslight Apsys software and the results were compared with the previous reported results. We also provide a brief overview of the phenomena, underlying theories, and potential possible solutions to these issues. Furthermore, we provide a brief discussion regarding micro-LEDs that have emission wavelengths ranging from yellow-green to red colors. We highlight the notable bandwidth enhancement for this paradigm and anticipate some exciting new research directions. Overall, this review paper provides a brief overview of the performance of VLC-based systems based on micro-LEDs and some of their possible applications.
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Affiliation(s)
- Konthoujam James Singh
- Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Wei-Ta Huang
- Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Semiconductor Research Center, Hon Hai Research Institute, Taipei 11492, Taiwan
| | - Fu-He Hsiao
- Semiconductor Research Center, Hon Hai Research Institute, Taipei 11492, Taiwan
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Wen-Chien Miao
- Semiconductor Research Center, Hon Hai Research Institute, Taipei 11492, Taiwan
- Department of Electrophysics, College of Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Tzu-Yi Lee
- Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yi-Hua Pai
- Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Hao-Chung Kuo
- Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Semiconductor Research Center, Hon Hai Research Institute, Taipei 11492, Taiwan
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Lee TY, Huang YM, Chiang H, Chao CL, Hung CY, Kuo WH, Fang YH, Chu MT, Wu CI, Lin CC, Kuo HC. Increase in the efficiency of III-nitride micro LEDs by atomic layer deposition. OPTICS EXPRESS 2022; 30:18552-18561. [PMID: 36221654 DOI: 10.1364/oe.455726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The effect of atomic-layer deposition (ALD) sidewall passivation on the enhancement of the electrical and optical efficiency of micro-light-emitting diode (µ-LED) is investigated. Various blue light µ-LED devices (from 5 × 5 µm2 to 100 × 100 µm2) with ALD-Al2O3 sidewall passivation were fabricated and exhibited lower leakage and better external quantum efficiency (EQE) comparing to samples without ALD-Al2O3 sidewall treatment. Furthermore, the EQE values of 5 × 5 and 10 × 10 µm2 devices yielded an enhancement of 73.47% and 66.72% after ALD-Al2O3 sidewall treatments process, and the output power also boosted up 69.3% and 69.9%. The Shockley-Read-Hall recombination coefficient can be extracted by EQE data fitting, and the recombination reduction in the ALD samples can be observed. The extracted surface recombination velocities are 551.3 and 1026 cm/s for ALD and no-ALD samples, respectively.
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Park J, Baek W, Geum DM, Kim S. Understanding the Sidewall Passivation Effects in AlGaInP/GaInP Micro-LED. NANOSCALE RESEARCH LETTERS 2022; 17:29. [PMID: 35230527 PMCID: PMC8888782 DOI: 10.1186/s11671-022-03669-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/15/2022] [Indexed: 05/11/2023]
Abstract
The passivation effects of sulfur treatment and Al2O3 passivation for AlGaInP/GaInP red micro-light-emitting-diodes (LEDs) were investigated in terms of the external quantum efficiency (EQE) and the current density showing the peak EQE (JEQE, peak). We systematically compared the electrical and optical characteristics of the micro-LEDs with and without passivation according to various sizes. Interestingly, our investigation indicated that simple electrical characteristics such as current density-voltage property are difficult to precisely reflect the minor change in electrical properties due to passivation when the device has the inherently low leakage current. Whereas the EQE was enhanced by 20% and JEQE, peak was largely shifted to a lower current density region at the LED with a size of 15 × 15 μm2. To examine the passivation effects, we carefully analyzed the EQE and JEQE, peak with the ABC recombination model, and established the methodology to investigate the influence of a sidewall in micro-LEDs. As a result, we extracted the surface recombination velocity regarding the surface passivation, showing a nearly 14% reduction with the passivation.
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Affiliation(s)
- Juhyuk Park
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Woojin Baek
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Dae-Myeong Geum
- Infromation and Electronics Research Institute, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
| | - Sanghyeon Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
- Infromation and Electronics Research Institute, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
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Chen PW, Hsiao PW, Chen HJ, Lee BS, Chang KP, Yen CC, Horng RH, Wuu DS. On the mechanism of carrier recombination in downsized blue micro-LEDs. Sci Rep 2021; 11:22788. [PMID: 34815512 PMCID: PMC8611052 DOI: 10.1038/s41598-021-02293-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/12/2021] [Indexed: 11/09/2022] Open
Abstract
The mechanism of carrier recombination in downsized μ-LED chips from 100 × 100 to 10 × 10 μm2 on emission performance was systemically investigated. All photolithography processes for defining the μ-LED pattern were achieved by using a laser direct writing technique. This maskless technology achieved the glass-mask-free process, which not only can improve the exposure accuracy but also save the development time. The multi-functional SiO2 film as a passivation layer successfully reduced the leakage current density of μ-LED chips compared with the μ-LED chips without passivation layer. As decreasing the chip size to 10 × 10 μm2, the smallest chip size exhibited the highest ideality factor, which indicated the main carrier recombination at the high-defect-density zone in μ-LED chip leading to the decreased emission performance. The blue-shift phenomenon in the electroluminescence spectrum with decreasing the μ-LED chip size was due to the carrier screening effect and the band filling effect. The 10 × 10 μm2 μ-LED chip exhibited high EQE values in the high current density region with a less efficiency droop, and the max-EQE value was 18.8%. The luminance of 96 × 48 μ-LED array with the chip size of 20 × 20 μm2 exhibited a high value of 516 nits at the voltage of 3 V.
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Affiliation(s)
- Po-Wei Chen
- Department of Materials Science and Engineering & Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Po-Wen Hsiao
- Department of Materials Science and Engineering & Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Hsuan-Jen Chen
- Department of Materials Science and Engineering & Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Bo-Sheng Lee
- Epileds Technologies, Incorporated, Tainan, 74148, Taiwan
| | - Kai-Ping Chang
- Department of Materials Science and Engineering & Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Chao-Chun Yen
- Department of Materials Science and Engineering & Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Ray-Hua Horng
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
| | - Dong-Sing Wuu
- Department of Materials Science and Engineering & Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 40227, Taiwan. .,Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou, 54561, Taiwan.
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Yeh YW, Lin SH, Hsu TC, Lai S, Lee PT, Lien SY, Wuu DS, Li G, Chen Z, Wu T, Kuo HC. Advanced Atomic Layer Deposition Technologies for Micro-LEDs and VCSELs. NANOSCALE RESEARCH LETTERS 2021; 16:164. [PMID: 34792678 PMCID: PMC8602599 DOI: 10.1186/s11671-021-03623-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/07/2021] [Indexed: 05/05/2023]
Abstract
In recent years, the process requirements of nano-devices have led to the gradual reduction in the scale of semiconductor devices, and the consequent non-negligible sidewall defects caused by etching. Since plasma-enhanced chemical vapor deposition can no longer provide sufficient step coverage, the characteristics of atomic layer deposition ALD technology are used to solve this problem. ALD utilizes self-limiting interactions between the precursor gas and the substrate surface. When the reactive gas forms a single layer of chemical adsorbed on the substrate surface, no reaction occurs between them and the growth thickness can be controlled. At the Å level, it can provide good step coverage. In this study, recent research on the ALD passivation on micro-light-emitting diodes and vertical cavity surface emitting lasers was reviewed and compared. Several passivation methods were demonstrated to lead to enhanced light efficiency, reduced leakage, and improved reliability.
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Affiliation(s)
- Yen-Wei Yeh
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Su-Hui Lin
- Fujian Engineering Research Center for Solid-State Lighting, Xiamen University National Integrated Circuit Industry and Education Integration Innovation Platform, School of Electronic Science and Engineering, Xiamen University, Xiamen, 361005, China
| | - Tsung-Chi Hsu
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Shouqiang Lai
- Fujian Engineering Research Center for Solid-State Lighting, Xiamen University National Integrated Circuit Industry and Education Integration Innovation Platform, School of Electronic Science and Engineering, Xiamen University, Xiamen, 361005, China
| | - Po-Tsung Lee
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Shui-Yang Lien
- School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen, 361024, China
| | - Dong-Sing Wuu
- Department of Materials Science and Engineering, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Guisen Li
- Unicompound Semiconductor Corporation, Putian, 351117, China
| | - Zhong Chen
- Fujian Engineering Research Center for Solid-State Lighting, Xiamen University National Integrated Circuit Industry and Education Integration Innovation Platform, School of Electronic Science and Engineering, Xiamen University, Xiamen, 361005, China
| | - Tingzhu Wu
- Fujian Engineering Research Center for Solid-State Lighting, Xiamen University National Integrated Circuit Industry and Education Integration Innovation Platform, School of Electronic Science and Engineering, Xiamen University, Xiamen, 361005, China.
| | - Hao-Chung Kuo
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
- Semiconductor Research Center, Hon Hai Research Institute, Taipei, 11492, Taiwan.
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Liu AC, Singh KJ, Huang YM, Ahmed T, Liou FJ, Liou YH, Ting CC, Lin CC, Li Y, Samukawa S, Kuo HC. Increase in the Efficiency of III-Nitride Micro-LEDs: Atomic-Layer Deposition and Etching. IEEE NANOTECHNOLOGY MAGAZINE 2021. [DOI: 10.1109/mnano.2021.3066393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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