Improvement of near-ultraviolet InGaN-GaN light-emitting diodes with an AlGaN electron-blocking layer grown at low temperature

Tun, Chun-Ju; Pan, Shyi-Ming; Chuo, Chang-Cheng; Sheu, Jinn-Kong; Tsai, Ching-En; Wang, Te-Chung; Chi, Gou–Chung

doi:10.1109/lpt.2003.818240

Cited by 37 publications

(5 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Foremost, the active region of nitride LED has evolved from the simplest heterostructure and single quantum well (QW) at the early stage to today’s multiple quantum wells (MQWs) with 5 periods QWs, and the QW number even can reach 8 or 10 for several commercialized high-power devices [ 14 – 17 ]. The EBL was proposed to block the leakage of electrons at high injection current density, even it also can impede the hole injection at some certain level [ 18 , 19 ]. For conventional high-power LEDs, the most substantial issue is the reduction of the external quantum efficiency (EQE) with the increased current density, which is known as efficiency droop.…”

Section: Introductionmentioning

confidence: 99%

Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density

Huang

et al. 2021

Nanoscale Res Lett

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density

Huang

et al. 2021

Nanoscale Res Lett

View full text Add to dashboard Cite

show abstract

“…Understanding the nature of vertical transport in nitride heterojunctions is essential for efficient device design. The use of AlGaN as an effective barrier material is especially important for electron blocking layers in light emitting diodes (LEDs) and laser diodes [1][2][3], resonant tunneling diodes [4][5][6], hot electron transistors [7,8], current aperture vertical electron transistors (CAVETs) [9,10], and other vertical device structures. Recent research in the III-Nitrides has focused on determining the role of natural alloy fluctuations in transport and optical processes [11][12][13].…”

mentioning

confidence: 99%

Vertical transport through AlGaN barriers in heterostructures grown by ammonia molecular beam epitaxy and metalorganic chemical vapor deposition

Browne

Fireman

Mazumder

et al. 2017

Semicond. Sci. Technol.

View full text Add to dashboard Cite

The results of vertical transport through AlGaN heterobarriers are presented for ammonia molecular beam epitaxy (NH 3 -MBE) on c-plane GaN on sapphire templates and on m-plane bulk GaN substrates, as well as by metalorganic chemical vapor deposition (MOCVD) on m-plane bulk GaN substrates. Experiments were performed to determine the role of the AlGaN alloy as an effective barrier to vertical transport, which is an essential component of both optoelectronic and power electronic devices. The alloy composition, thickness, and doping levels of the AlGaN layers, as well as substrate orientation, were systematically varied to examine their influence on electron transport. Atom probe tomography (APT) was used to directly determine the alloy composition at the atomic scale to reveal the presence of random alloy fluctuations which provides insight into the nature of the observed transport.

show abstract

“…To achieve high efficiency, this problem must be solved. 80,81 The conventional AlGaN EBL works as an obstacle for escaping electrons. 82 High composition of aluminum in AlGaN causes severer downward band bending at the interface of the last quantum barrier and EBL, thus, increasing the effective barrier further.…”

Section: Thickness-graded Active Region or Thickness-gradedmentioning

confidence: 99%

Review—A Survey of Simulations on Device Engineering of GaN-Based Light-Emitting Diodes

Usman

Anwar

Munsif

2020

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

In InGaN-based light-emitting diodes, efficiency droop at high current density degrades device performance. Different strategies have been proposed by researchers to enhance the performance of InGaN-based light-emitting diodes numerically. We present a survey of the notable reported efficient simulated device structures, to date. We also discuss the simulation methodology employed in the state-of-the-art numerical simulators to study InGaN-based light-emitting diodes. Our survey gathers the influence of the layer engineering of each layer on the device performance of light-emitting diodes. Thus, different reported structures address the efficiency droop problem differently, thus, showing better optoelectronic properties as compared to the conventional structure.

show abstract

Improvement of near-ultraviolet InGaN-GaN light-emitting diodes with an AlGaN electron-blocking layer grown at low temperature

Cited by 37 publications

References 11 publications

Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density

Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density

Vertical transport through AlGaN barriers in heterostructures grown by ammonia molecular beam epitaxy and metalorganic chemical vapor deposition

Review—A Survey of Simulations on Device Engineering of GaN-Based Light-Emitting Diodes

Contact Info

Product

Resources

About