Performance improvement of AlGaN-based ultraviolet light-emitting diodes by amending inverted-Y-shaped barriers with alternate doped Si and Mg

Hou, Yufei; Guo, Zhiyou; Liu, Yang; Guo, Min; Huang, Jing; Yao, Shunyu; Xiu, Zhang; Gong, Xuan; Xu, Z. Y.

doi:10.1016/j.spmi.2017.04.017

Cited by 13 publications

(7 citation statements)

References 21 publications

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“…To simultaneously achieve efficient current injection and sufficient carrier confinement in AlGaN UV light emitters, compositionally graded AlGaN quantum structures (QWs [66][67][68][69][70], QBs [71][72][73][74], a LQB [75,76], and p-EBLs [77][78][79]) have been tentatively investigated and employed. Such structures can tailor the polarization fields, alleviate band bending, and consequently either increase the electron barrier height or decrease the hole barrier height, to effectively control the carrier transport, confinement, and recombination process.…”

Section: Manipulation Of Carrier Transport Via Energy Band Engineeringmentioning

confidence: 99%

Compositionally graded III-nitride alloys: building blocks for efficient ultraviolet optoelectronics and power electronics

Zhang¹,

Huang²,

Song³

et al. 2021

Rep. Prog. Phys.

132

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Wide bandgap aluminum gallium nitride (AlGaN) semiconductor alloys have established themselves as the key materials for building ultraviolet (UV) optoelectronic and power electronic devices. However, further improvements to device performance are lagging, largely due to the difficulties in precisely controlling carrier behavior, both carrier generation and carrier transport, within AlGaN-based devices. Fortunately, it has been discovered that instead of using AlGaN layers with fixed Al compositions, by grading the Al composition along the growth direction, it is possible to (1) generate high-density electrons and holes via polarization-induced doping; (2) manipulate carrier transport behavior via energy band modulation, also known as ‘band engineering’. Consequently, such compositionally graded AlGaN alloys have attracted extensive interest as promising building blocks for efficient AlGaN-based UV light emitters and power electronic devices. In this review, we focus on the unique physical properties of graded AlGaN alloys and highlight the key roles that such graded structures play in device exploration. Firstly, we elaborate on the underlying mechanisms of efficient carrier generation and transport manipulation enabled by graded AlGaN alloys. Thereafter, we comprehensively summarize and discuss the recent progress in UV light emitters and power electronic devices incorporating graded AlGaN structures. Finally, we outline the prospects associated with the implementation of graded AlGaN alloys in the pursuit of high-performance optoelectronic and power electronic devices.

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Section: Manipulation Of Carrier Transport Via Energy Band Engineeringmentioning

confidence: 99%

Compositionally graded III-nitride alloys: building blocks for efficient ultraviolet optoelectronics and power electronics

Zhang¹,

Huang²,

Song³

et al. 2021

Rep. Prog. Phys.

132

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“…Planar DUV LEDs suffer from the high density of dislocations in the films which hurt the device performance. To solve the problem of large dislocation density and low p-type doping efficiency for conventional planar DUV LEDs, a unique DUV LED with a nearly defect-free AlGaN TJ core-shell nanowire structure was proposed by Mi Lattice-matched insertion layer [91] Graded EBL Linearly graded Al composition EBL [82,84] Triangular shape graded EBL [85,86] Multilayers in EBL MQB or SL EBL [78,79,81] Gradient EBL [127] GMQB or GSL EBL [82,83] LQB design Change Al-composition in LQB Linearly graded LQB [100] Higher Al-content LQB [98] Multilayers in LQB MQB or SL LQB [101,128] GSL LQB [129] QB design Graded QB Linearly graded QB [103] Triangular shape graded QB [86] Inverted-Y-shaped QB [130] Insertion layer in QB Introducing a single spike barrier [106,131] Insertion a layer in the middle of QB [107,132] QW design Graded QW Linearly graded QW [111,133] Parabolic QW [133,96] Step-like QW [108] Quantum confinement GaN/AlN quantum structure [113,[134][135][136] (Continued)…”

Section: Tunnel Junction Implementationmentioning

confidence: 99%

Band engineering of III-nitride-based deep-ultraviolet light-emitting diodes: a review

Ren

Liu

et al. 2019

J. Phys. D: Appl. Phys.

121

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III-nitride deep ultraviolet (DUV) light-emitting diodes (LEDs) have been identified as promising candidates for energy-efficient, environment-friendly and robust UV lighting sources with potential applications in water/air purification, sterilization, and bio-sensing. However, the performance of state-of-art DUV LEDs is far from satisfactory for commercialization due to their low internal quantum efficiency, large current leakage and efficiency droop at high current injection, etc. Extensive efforts have been devoted to properly designing the band structures of such luminescent devices to enhance their output power. In this review, we summarize the recent progress of various energy band designs and of the engineering of DUV LEDs, with particular attention paid to the various approaches in band engineering of electron-blocking layers, quantum wells, quantum barriers and the implementation of many novel structures such as tunnel junctions and ultrathin quantum heterostructures utilized to enhance their efficiency. These inspirational approaches pave the way towards the next generation of greener and more efficient UV sources suitable for practical applications.

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“…Meanwhile, the electric field is also decreased by using two parts linearly graded quantum barriers, and according to reduce the electric field the quantum-confined Stark effect and the bend of the energy band get relieved. each barrier; [32] Y-shaped barriers with alternate doped Si and Mg; [33] with step-like QBs. [34] In addition, some scholars have also studied the influence of chip size on the optical and electrical properties of DUV-LEDs.…”

Section: Introductionmentioning

confidence: 99%

“…[ 18,19 ] Besides, articles on QW structures have been widely published in recent years: graded quantum QWs/QBs; [ 20,21 ] varying trapezoidal bottom well width [ 22 ] ; staggered InGaN QWs; [ 23–25 ] zigzag QWs and W‐shaped QWs; [ 26,27 ] and step‐stage multiple quantum well (MQW). [ 28 ] Of course, some strategies for regulating band of QB have been reported to ameliorate polarized electric field in MQWs and reduce the quantum‐confined stark effect (QCSE) to improve internal quantum efficiency: for example, inserting single spike barriers [ 29 ] ; graded Al‐content AlGaN insertion layer; [ 30 ] partially graded QBs; [ 31 ] linear increment of Al composition by 0.03 along the growth direction in each barrier; [ 32 ] Y‐shaped barriers with alternate doped Si and Mg; [ 33 ] with step‐like QBs. [ 34 ] In addition, some scholars have also studied the influence of chip size on the optical and electrical properties of DUV‐LEDs.…”

Section: Introductionmentioning

confidence: 99%

Performance of Improvement of AlGaN‐Based Deep UV Light‐Emitting Diode with Two Parts Linearly Graded Barriers

Ren

Lin

Cai

et al. 2023

Physica Status Solidi (a)

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Herein, a novel AlGaN‐based multiple quantum well (MQW) deep UV light‐emitting diode (DUV‐LED) structure with two parts linearly graded barriers is presented. The simulation result shows that at a current of 50 mA, the light output power of the DUV‐LED with two parts linearly graded barrier MQWs has significant improvement as compared to stationary barriers. The electroluminescence spectrum and radiative recombination rate of novel DUV‐LEDs are also larger more than twice that of the conventional QW structure. The reason is that the injection efficiency of holes is increased which helps improve the hole and electron concentration in the active area. Meanwhile, the electric field is also decreased by using two parts linearly graded quantum barriers, and according to reduce the electric field the quantum‐confined Stark effect and the bend of the energy band get relieved.

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Performance improvement of AlGaN-based ultraviolet light-emitting diodes by amending inverted-Y-shaped barriers with alternate doped Si and Mg

Cited by 13 publications

References 21 publications

Compositionally graded III-nitride alloys: building blocks for efficient ultraviolet optoelectronics and power electronics

Compositionally graded III-nitride alloys: building blocks for efficient ultraviolet optoelectronics and power electronics

Band engineering of III-nitride-based deep-ultraviolet light-emitting diodes: a review

Performance of Improvement of AlGaN‐Based Deep UV Light‐Emitting Diode with Two Parts Linearly Graded Barriers

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