Yen‐Kuang Kuo

National Changhua University of Education

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Jih‐Yuan Chang

National Changhua University of Education

Sheng‐Horng Yen

Epistar (Taiwan)

Bo-Ting Liou

Hsiuping University of Science and Technology

Man-Fang Huang

National Changhua University of Education

Miao‐Chan Tsai

National Changhua University of Education

Fang‐Ming Chen

Zhejiang Chinese Medical University

Ya‐Hsuan Shih

National Cheng Kung University

Hao‐Chung Kuo

National Yang Ming Chiao Tung University

Yi-An Chang

National Tsing Hua University

Milton Birnbaum

The Aerospace Corporation

Cooperative Institutions

National Changhua University of Education

National Yang Ming Chiao Tung University

National Taiwan University

National Cheng Kung University

National Central University

Chinese Academy of Sciences

Industrial Technology Research Institute

National Tsing Hua University

University of Southern California

Epistar (Taiwan)

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Design of GaN-Based Multicolor Tunnel-Junction Light-Emitting Diodes

IEEE Transactions on Electron Devices (2017)

Ya‐Hsuan Shih Jih‐Yuan Chang Yen‐Kuang Kuo Fang‐Ming Chen Man-Fang Huang

The design of monolithic multicolor tunnel-junction (TJ) light-emitting diodes (LEDs) are investigated numerically. This paper primarily aims to design and study monolithic TJ LED devices that possess high luminous efficiency and wide color gamut using a simple fabrication process. First, the characteristics of green and blue single LEDs are explored. Nonuniform carrier distribution inside quantum wells (QWs), which is due to the deep QWs and severe polarization effect, is observed for both single LEDs under study. Based on structural analysis of the single LEDs, streamline dual-color and broadband TJ LED structures, in which the blue unit LED has two pairs of 3-nm-thick QWs and the green unit LED has 3-nm-thick single QW, are designed and investigated. Specifically, monolithic dual-color blue/green (459/530 nm) TJ LED is proposed and analyzed using effective n ⁺ -GaN/i-In _0.2 Ga _0.8 N/p ⁺ -GaN TJ. Furthermore, broadband TJ LED with simulated full width at half maximum of around 100 nm is achieved.

10.1109/ted.2017.2773660

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Citations (6)

Influence of polarization-matched AlGaInN barriers in blue InGaN light-emitting diodes

Optics Letters (2012)

Jih-Yuan Chang Yen‐Kuang Kuo

The advantages of blue InGaN light-emitting diodes with low bandgap energy and polarization-matched AlGaInN barriers are demonstrated numerically. Simulation results show that, besides the common benefit of enhanced electron–hole spatial overlap in the quantum well from the polarization-matched condition, the lower bandgap energy barriers can have additional advantages of more uniform carrier distribution among quantum wells while maintaining sufficient electron confinement. The internal quantum efficiencies of all the polarization-matched structures under study exhibit less severe efficiency droop, which is presumably attributed to the suppression of Auger recombination.

Auger effect

Wide-bandgap semiconductor

10.1364/ol.37.001574

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Citations (17)

Experimental and theoretical analysis on ultraviolet 370-nm AlGaInN light-emitting diodes

Yi-An Chang Sheng‐Horng Yen Tsung-Hsine Ko Te‐Chung Wang Chun‐Yi Lu

A 370-nm LED with an AlGaN electron-block layer is fabricated. Simulation results suggest that optimal performance is obtained when the LED has more than 3 wells and the AlGaN has Al composition of 19-21%.

Ultraviolet

Wide-bandgap semiconductor

10.1109/cleo.2006.4628798

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Citations (0)

Numerical study for 1.55-μm AlGaInAs/InP semiconductor lasers

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2006)

Bo-Ting Liou Sheng‐Horng Yen Ming-Wei Yao Mei-Ling Chen Yen‐Kuang Kuo

Referred to the laser structure and its experimental results obtained by Selmic et al. and Liu et al., optimized active structure for the 1.55-μm quantum well lasers based on AlGaInAs material system is investigated. A structure with 1.2% compressive-strained wells and a p-type AlInAs electron stopper layer of 20 nm thickness and 5×10²³ m^-3 doping concentration is suggested. Using this structure the threshold current is reduced to 17.8 mA, and the electron overflow percentage is decreased to 1.74% at 330 K. Furthermore, the characteristic temperatures of threshold currents are enhanced to 55.6 K, 67.0 K, and 43.3 K in operating temperature ranges of 300 K~350 K, 300 K~330 K, and 330 K~350 K, respectively.

10.1117/12.685959

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Citations (10)

Achievement of 110-nm-Wide Spectral Width in Monolithic Tunnel-Junction Light-Emitting Diode

IEEE Journal of Quantum Electronics (2021)

Man-Fang Huang Ya‐Hsuan Shih Jih‐Yuan Chang Yen‐Lung Huang Jinn‐Kong Sheu

Characterization and structural design on monolithic stacked InGaN light-emitting diode (LED) are investigated numerically in an attempt to pursue multicolor light emission and wide spectral width. Crucial physical properties such as the energy band configurations, carrier distributions, and interband transitions are analyzed in detail, which are also utilized as an aid to justify the desired characteristics of the LED structures under study. The compositions of multi-quantum wells, as well as the thicknesses of quantum barriers in each unit stacked LED are appropriately adjusted to simplify the tandem LED structure and optimize the overall emission spectra. Upon optimization, a monolithic tunnel-junction LED with an emission spectral width of approximately 110 nm, full width at half maximum, is demonstrated with only three unit stacked LEDs and two tunnel junctions.

Spectral width

Tunnel junction

Tandem

Tunnel diode

10.1109/jqe.2021.3079419

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Citations (1)

Band-Engineered Structural Design of High-Performance Deep-Ultraviolet Light-Emitting Diodes

Crystals (2021)

Jih‐Yuan Chang Man-Fang Huang Chih-Yung Huang Shih-Chin Lin Ching‐Chiun Wang

In this study, systematic structural design was investigated numerically to probe into the cross-relating influences of n-AlGaN layer, quantum barrier (QB), and electron-blocking layer (EBL) on the output performance of AlGaN deep-ultraviolet (DUV) light-emitting diodes (LEDs) with various Al compositions in quantum wells. Simulation results show that high-Al-composition QB and high-Al-composition EBL utilized separately are beneficial for the enhancement of carrier confinement, while the wall-plug efficiency (WPE) degrades dramatically if both high-Al-composition QB and EBL are existing in a DUV LED structure simultaneously. DUV LEDs may be of great optical performance with appropriate structural design by fine-tuning the material parameters in n-AlGaN layer, QB, and EBL. The design curves provided in this paper can be very useful for the researchers in developing the DUV LEDs with a peak emission wavelength ranging from 255 nm to 285 nm.

Ultraviolet

Quantum Efficiency

10.3390/cryst11030271

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Citations (1)

Efficiency enhancement of blue InGaN LEDs with indium composition graded InGaN barriers

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2011)

Tsun-Hsin Wang Jih‐Yuan Chang Miao-Chan Tsai Yen‐Kuang Kuo

In recent literatures, the quantum efficiency of conventional blue InGaN light-emitting diodes (LEDs) is quite limited under relatively high driving current with conventional GaN barriers due presumably to the poor injection efficiency of hole. In this study, the efficiency enhancement of blue InGaN LEDs with indium composition graded InGaN barriers is proposed. The energy band diagram, carrier concentration in the quantum wells, diagram of hole current, radiative recombination rate, L-I curves, and internal quantum efficiency are investigated numerically. The simulation results show that the InGaN LED with graded InGaN barriers has better performance over its conventional counterpart with GaN barriers due to enhanced efficiency of hole injection. The simulation results also suggest that under relatively high current injection, the internal quantum efficiency and output light power are markedly improved when the traditional GaN barriers are replaced by graded InGaN barriers. According to the improved optical properties, the new-designed LED has promising potential in solid state lighting.

Indium gallium nitride

Quantum Efficiency

Band diagram

Solid-State Lighting

Wide-bandgap semiconductor

10.1117/12.874909

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Citations (11)

Theoretical investigation of Auger recombination on internal quantum efficiency of blue light-emitting diodes

Applied Physics A (2009)

S. H. Yen M.-C. Tsai Meng-Lun Tsai Yinchu Shen T. C. Hsu

Quantum Efficiency

Auger effect

10.1007/s00339-009-5298-8

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Citations (18)

Tunnel-Junction Light-Emitting Diodes

CRC Press eBooks (2017)

Yen‐Kuang Kuo Jih-Yuan Chang Ya-Hsuan Shih Fang‐Ming Chen Miao‐Chan Tsai

The use of p-n tunnel junctions for applications in gallium nitride (GaN)-based electronic and optoelectronic devices has become increasingly attractive. The probability of interband tunneling across a potential barrier is mainly governed by the tunneling barrier height determined by the bandgap and the tunneling barrier thickness. For the application in solid-state lighting, the development of high-efficiency and high-power III-nitride light-emitting diodes (LED) is required. Direct interband tunneling in a p-n junction between the valence and conduction bands in an external applied electric field is commonly referred to as a tunnel junction, or an Esaki junction, or a Zener tunneling diode under reverse bias. The monolithic structure with multiple LEDs stacked by tunnel junctions was introduced. The concept of stacking identical LED structures with tunnel junctions is investigated for green InGaN LEDs to probe its effectiveness. The chapter explores several design approaches of the GaN-based polarization-assisted tunnel junctions.

Tunnel junction

10.1201/9781315152301-16

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Citations (2)

Design and Optimization of Electron-Blocking Layer in Deep Ultraviolet Light-Emitting Diodes

IEEE Journal of Quantum Electronics (2019)

Yen‐Kuang Kuo Fang‐Ming Chen Jih‐Yuan Chang Man-Fang Huang Bo-Ting Liou

Optical and electrical performance and the relevant physical properties of deep ultraviolet (DUV) AlGaN-based light-emitting diodes (LEDs) are numerically investigated. The influence of bulk AlGaN electron-blocking layer (EBL) with various Al compositions and Mg-doping concentrations on the output performance of DUV LEDs is systemically explored. Simulation results show that the DUV LED with bulk Al _0.85 Ga _0.15 N EBL with a relatively low Mg-doping concentration of 2×10 ¹⁹ cm ^-3 may have high wall-plug efficiency. The LED structure with Al _0.55 Ga _0.45 N/Al _0.75 Ga _0.25 N superlattice (SL) EBL is proposed in this study, which is shown to have high wall-plug efficiency similar to the LED with bulk Al _0.85 Ga _0.15 N EBL while the Al composition of AlGaN EBL can be effectively reduced. The proposed LED structure with SL EBL provides a practical way to fabricate high-crystalline-quality and high-efficiency DUV LEDs.

Ultraviolet

10.1109/jqe.2019.2957575

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Citations (22)