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38 pages, 10775 KiB

Open AccessReview

Comparison of Thin-Film Lithium Niobate, SOH, and POH for Silicon Photonic Modulators

by Tai-Cheng Yu, An-Chen Liu, Wei-Ta Huang, Chang-Chin Wu, Chung-Hsun Li, Tsung-Sheng Kao, Shu-Wei Chang, Chin-Wei Sher, Huang-Yu Lin, Chi-Wai Chow and Hao-Chung Kuo

Photonics 2025, 12(5), 429; https://doi.org/10.3390/photonics12050429 - 29 Apr 2025

Cited by 2 | Viewed by 2703

Abstract

Optical modulators are indispensable components in optical communication systems and must be designed to minimize insertion loss, reduce driving voltage, and enhance linearity. State-of-the-art silicon modulator technology has limitations in terms of power, performance, and spatial size. The addition of materials such as [...] Read more.

Optical modulators are indispensable components in optical communication systems and must be designed to minimize insertion loss, reduce driving voltage, and enhance linearity. State-of-the-art silicon modulator technology has limitations in terms of power, performance, and spatial size. The addition of materials such as thin-film lithium niobate (TFLN), silicon–organic hybrids (SOH), and plasma–organic hybrids (POH) has improved the modulation performance in silicon photonics. An evaluation of the differences among these modulators and their respective performance characteristics is conducted. Full article

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8 pages, 2013 KiB

Open AccessArticle

Study of High Polarized Nanostructure Light-Emitting Diode

by Kuo-Hsiung Chu, Jo-Hsiang Chen, Kuo-Bin Hong, Yu-Ming Huang, Shih-Wen Chiu, Fu-Yao Ke, Chia-Wei Sun, Tsung-Sheng Kao, Chin-Wei Sher and Hao-Chung Kuo

Crystals 2022, 12(4), 532; https://doi.org/10.3390/cryst12040532 - 11 Apr 2022

Cited by 4 | Viewed by 3116

Abstract

In this study, we investigated the characteristic difference between the two different configurations of the three-dimensional shell–core nanorod LED. We achieve a degree of polarization of 0.545 for tip-free core–shell nanorod LED and 0.188 for tip core–shell nanorod LED by combining the three-dimensional [...] Read more.

In this study, we investigated the characteristic difference between the two different configurations of the three-dimensional shell–core nanorod LED. We achieve a degree of polarization of 0.545 for tip-free core–shell nanorod LED and 0.188 for tip core–shell nanorod LED by combining the three-dimensional (3D) structure LED with photonic crystal. The ability of low symmetric modes generated by photonic crystals to enhance degree of polarization has been demonstrated through simulations of photonic crystals. In addition, light confinement in GaN-based nanorod structures is induced by total internal reflection at the GaN/air interface. The combination of 3D core–shell nanorod LED and photonic crystals cannot only produce a light source with a high degree of polarization, but also a narrow divergence angle up to 56°. These 3D LEDs may pave the way for future novel optoelectronic components. Full article

(This article belongs to the Special Issue III-Nitride-Based Light-Emitting Devices)

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9 pages, 3629 KiB

Open AccessArticle

High Stability of Liquid-Typed White Light-Emitting Diode with Zn_0.8Cd_0.2S White Quantum Dots

by Chin-Chuan Huang, Kuo-Hsiung Chu, Chin-Wei Sher, Chun-Liang Lin, Yan-Kuin Su, Chia-Wei Sun and Hao-Chung Kuo

Coatings 2021, 11(4), 415; https://doi.org/10.3390/coatings11040415 - 2 Apr 2021

Cited by 3 | Viewed by 2717

Abstract

In this study, we demonstrate a new design of white light-emitting diode (WLED) with high stability and luminous efficiency as well as positive aging. Colloidal ternary Zn_0.8Cd_0.2S (named Zn_0.8) white quantum dots (WQDs) were prepared by chemical [...] Read more.

In this study, we demonstrate a new design of white light-emitting diode (WLED) with high stability and luminous efficiency as well as positive aging. Colloidal ternary Zn_0.8Cd_0.2S (named Zn_0.8) white quantum dots (WQDs) were prepared by chemical route and dispersed in xylene, integrating them into an ultraviolet light-emitting diode (UV-LED) to form WQD-white light emitting diode (WQD-WLED). High efficiency, high color quality and excellent reliability of WQD-WLED with neutral white correlated color temperature (CCT) can be obtained. The experimental results indicate that the stability of relative luminous efficiency and color rendering index (CRI) of the WQD-WLED can reach up to 160 and 82%, respectively. Moreover, the WQD-WLED can operate more than 1000 h under 100 mA, and the quantity of WQDs in the glass package can be reduced. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductors: Growth, Characterization, Devices and System Applications)

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11 pages, 3337 KiB

Open AccessArticle

Ultrawide Color Gamut Perovskite and CdSe/ZnS Quantum-Dots-Based White Light-Emitting Diode with High Luminous Efficiency

by Chih-Hao Lin, Chieh-Yu Kang, Akta Verma, Tingzhu Wu, Yung-Min Pai, Tzu-Yu Chen, Chun-Lin Tsai, Ya-Zhu Yang, S.K. Sharma, Chin-Wei Sher, Zhong Chen, Po-Tseng Lee, Shu-Ru Chung and Hao-Chung Kuo

Nanomaterials 2019, 9(9), 1314; https://doi.org/10.3390/nano9091314 - 14 Sep 2019

Cited by 23 | Viewed by 6023

Abstract

We demonstrate excellent color quality of liquid-type white light-emitting diodes (WLEDs) using a combination of green light-emitting CsPbBr₃ and red light-emitting CdSe/ZnS quantum dots (QDs). Previously, we reported red (CsPbBr_1.2I_1.8) and green (CsPbBr₃) perovskite QDs (PQDs)-based [...] Read more.

We demonstrate excellent color quality of liquid-type white light-emitting diodes (WLEDs) using a combination of green light-emitting CsPbBr₃ and red light-emitting CdSe/ZnS quantum dots (QDs). Previously, we reported red (CsPbBr_1.2I_1.8) and green (CsPbBr₃) perovskite QDs (PQDs)-based WLEDs with high color gamut, which manifested fast anion exchange and stability issues. Herein, the replacement of red PQDs with CdSe/ZnS QDs has resolved the aforementioned problems effectively and improved both stability and efficiency. Further, the proposed liquid-type device possesses outstanding color gamut performance (132% of National Television System Committee and 99% of Rec. 2020). It also shows a high efficiency of 66 lm/W and an excellent long-term operation stability for over 1000 h. Full article

(This article belongs to the Special Issue Quantum Dots and Micro-LED Display)

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9 pages, 8552 KiB

Open AccessArticle

Ultra-High Light Extraction Efficiency and Ultra-Thin Mini-LED Solution by Freeform Surface Chip Scale Package Array

by Che-Hsuan Huang, Chieh-Yu Kang, Shu-Hsiu Chang, Chih-Hao Lin, Chun-Yu Lin, Tingzhu Wu, Chin-Wei Sher, Chien-Chung Lin, Po-Tsung Lee and Hao-Chung Kuo

Crystals 2019, 9(4), 202; https://doi.org/10.3390/cryst9040202 - 11 Apr 2019

Cited by 26 | Viewed by 6216

Abstract

In this study, we present a novel type of package, freeform-designed chip scale package (FDCSP), which has ultra-high light extraction efficiency and bat-wing light field. For the backlight application, mainstream solutions are chip-scale package (CSP) and surface-mount device package (SMD). Comparing with these [...] Read more.

In this study, we present a novel type of package, freeform-designed chip scale package (FDCSP), which has ultra-high light extraction efficiency and bat-wing light field. For the backlight application, mainstream solutions are chip-scale package (CSP) and surface-mount device package (SMD). Comparing with these two mainstream types of package, the light extraction efficiency of CSP, SMD, and FDCSP are 88%, 60%, and 96%, respectively. In addition to ultra-high light extraction efficiency, because of the 160-degree bat-wing light field, FDCSP could provide a thinner and low power consumption mini-LED solution with a smaller number of LEDs than CSP and SMD light source array. Full article

(This article belongs to the Special Issue GaN-Based Optoelectronic Materials and Light Emitting Devices)

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7 pages, 3021 KiB

Open AccessArticle

Design and Fabrication of the Reliable GaN Based Vertical-Cavity Surface-Emitting Laser via Tunnel Junction

by Chih-Chiang Shen, Yun-Ting Lu, Yen-Wei Yeh, Cheng-Yuan Chen, Yu-Tzu Chen, Chin-Wei Sher, Po-Tsung Lee, Ya-Hsuan Shih, Tien-Chang Lu, Tingzhu Wu, Ching-Hsueh Chiu and Hao-Chung Kuo

Crystals 2019, 9(4), 187; https://doi.org/10.3390/cryst9040187 - 1 Apr 2019

Cited by 19 | Viewed by 5284

Abstract

In this study, we theoretically designed and experimentally fabricated an InGaN vertical-cavity surface-emitting laser (VCSEL) with a tunnel junction (TJ) structure. From numerical simulation results, the optical loss of the device can be reduced by a TJ structure. Additionally, the leakage current of [...] Read more.

In this study, we theoretically designed and experimentally fabricated an InGaN vertical-cavity surface-emitting laser (VCSEL) with a tunnel junction (TJ) structure. From numerical simulation results, the optical loss of the device can be reduced by a TJ structure. Additionally, the leakage current of the VCSEL with TJ structure was much smaller than that of the VCSEL with an Indium-Tin-Oxide (ITO) layer. We have been demonstrated that laser output performance is improved by using the TJ structure when compared to the typical VCSEL structure of the ITO layer. The output power obtained at 2.1 mW was enhanced by a factor of 3.5 by the successful reduction of threshold current density (J_th) from 12 to 8.5 kA/cm², and the enlarged slope efficiency was due to less absorption in VCSEL with a TJ structure. Finally, the samples passed the high temperature (70 °C) and high operation current (1.5 × J_th) test for over 500 h. Full article

(This article belongs to the Special Issue GaN-Based Optoelectronic Materials and Light Emitting Devices)

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9 pages, 3977 KiB

Open AccessArticle

Square Column Structure of High Efficiency, Reliable, Uniformly Flexible LED Devices

by Chih-Hao Lin, Yung-Min Pai, Chieh-Yu Kang, Huang-Yu Lin, Chun-Fu Lee, Xin-Yin Chen, Hsien-Hao Tu, Jin-Jia Yang, Cheng-Huan Chen, Chien-Chung Lin, Po-Tsung Lee, Chin-Wei Sher and Hao-Chung Kuo

Crystals 2018, 8(12), 472; https://doi.org/10.3390/cryst8120472 - 16 Dec 2018

Cited by 3 | Viewed by 4577

Abstract

This study demonstrates that flexible white LEDs, doped with diffusion particles and with a square column structure, have excellent luminosity, uniformity, and bending reliability. This large area (5 cm × 5 cm) square column flexible device had a smaller thickness (2 mm), and [...] Read more.

This study demonstrates that flexible white LEDs, doped with diffusion particles and with a square column structure, have excellent luminosity, uniformity, and bending reliability. This large area (5 cm × 5 cm) square column flexible device had a smaller thickness (2 mm), and enhancements in both luminous efficiency (29.5%) and uniformity (44.6%) compared to the characteristics of the 6 mm reference sample. Optimization of the reflective layer coating for the square column, flexible white LED was achieved with a higher luminous efficiency (171 lm/w) and uniformity (92%). We designed a novel lightning bolt electrode to improve reliability and bendability. After the bending test, the blue flexible LED had a lower bending diameter (10 mm) but more bending circles (increased to 2000 times. Full article

(This article belongs to the Special Issue GaN-Based Optoelectronic Materials and Light Emitting Devices)

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9 pages, 1800 KiB

Open AccessArticle

Novel Method for Estimating Phosphor Conversion Efficiency of Light-Emitting Diodes

by Chih-Hao Lin, Che-Hsuan Huang, Yung-Min Pai, Chung-Fu Lee, Chien-Chung Lin, Chia-Wei Sun, Cheng-Huan Chen, Chin-Wei Sher and Hao-Chung Kuo

Crystals 2018, 8(12), 442; https://doi.org/10.3390/cryst8120442 - 27 Nov 2018

Cited by 7 | Viewed by 4846

Abstract

This study presents a novel method for estimating the phosphor conversion efficiency of white light-emitting diodes (WLEDs) with different ratios of phosphors. Numerous attempts have been made for predicting the phosphor conversion efficiency of WLEDs using Monte Carlo ray tracing and the Mie [...] Read more.

This study presents a novel method for estimating the phosphor conversion efficiency of white light-emitting diodes (WLEDs) with different ratios of phosphors. Numerous attempts have been made for predicting the phosphor conversion efficiency of WLEDs using Monte Carlo ray tracing and the Mie scattering theory. However, because efficiency depends on the phosphor concentration, obtaining a tight match between this model and the experimental results remains a major challenge. An accurate prediction depends on various parameters, including particle size, morphology, and packaging process criteria. Therefore, we developed an efficient model that can successfully correlate the total absorption ratio to the phosphor concentration using a simple equation for estimating the spectra and lumen output. The novel and efficient method proposed here can accelerate WLED development by reducing costs and saving fabrication time. Full article

(This article belongs to the Special Issue GaN-Based Optoelectronic Materials and Light Emitting Devices)

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17 pages, 13919 KiB

Open AccessEditor’s ChoiceReview

Mini-LED and Micro-LED: Promising Candidates for the Next Generation Display Technology

by Tingzhu Wu, Chin-Wei Sher, Yue Lin, Chun-Fu Lee, Shijie Liang, Yijun Lu, Sung-Wen Huang Chen, Weijie Guo, Hao-Chung Kuo and Zhong Chen

Appl. Sci. 2018, 8(9), 1557; https://doi.org/10.3390/app8091557 - 5 Sep 2018

Cited by 686 | Viewed by 53574

Abstract

Displays based on inorganic light-emitting diodes (LED) are considered as the most promising one among the display technologies for the next-generation. The chip for LED display bears similar features to those currently in use for general lighting, but it size is shrunk to [...] Read more.

Displays based on inorganic light-emitting diodes (LED) are considered as the most promising one among the display technologies for the next-generation. The chip for LED display bears similar features to those currently in use for general lighting, but it size is shrunk to below 200 microns. Thus, the advantages of high efficiency and long life span of conventional LED chips are inherited by miniaturized ones. As the size gets smaller, the resolution enhances, but at the expense of elevating the complexity of fabrication. In this review, we introduce two sorts of inorganic LED displays, namely relatively large and small varieties. The mini-LEDs with chip sizes ranging from 100 to 200 μm have already been commercialized for backlight sources in consumer electronics applications. The realized local diming can greatly improve the contrast ratio at relatively low energy consumptions. The micro-LEDs with chip size less than 100 μm, still remain in the laboratory. The full-color solution, one of the key technologies along with its three main components, red, green, and blue chips, as well color conversion, and optical lens synthesis, are introduced in detail. Moreover, this review provides an account for contemporary technologies as well as a clear view of inorganic and miniaturized LED displays for the display community. Full article

(This article belongs to the Special Issue Group III-V Nitride Semiconductor Microcavities and Microemitters)

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