Performance Improvements for AlGaN-Based Deep Ultraviolet Light-Emitting Diodes With the p-Type and Thickened Last Quantum Barrier

Bao, Xianglong; Sun, Pai; Liu, Songqin; Ye, Chunya; Li, Shuping; Kang, Junyong

doi:10.1109/jphot.2014.2387253

Cited by 42 publications

(10 citation statements)

References 54 publications

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“… However, the optical output power of current UVC LEDs drops significantly as the light emission wavelength gets shorter. Those LEDs suffer from poor hole injection efficiency in high‐Al‐content p‐type AlGaN, low internal quantum efficiency (IQE) caused by large‐lattice‐mismatch heteroepitaxy, and strong quantum‐confined Stark effect (QCSE), as well as the absorption by the nontransparent GaN contact layers …”

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confidence: 99%

Deep Ultraviolet Light Source from Ultrathin GaN/AlN MQW Structures with Output Power Over 2 Watt

Wang

Rong

Иванов

et al. 2019

Advanced Optical Materials

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which are environmentally friendly and enable portability and high efficiency. Up to date, great progress has been made on the UVC light-emitting diodes (LEDs) by using active regions of AlGaN multiple quantum wells (MQWs) .[8-14] However, the optical output power of current UVC LEDs drops significantly as the light emission wavelength gets shorter. Those LEDs suffer from poor hole injection efficiency in high-Al-content p-type AlGaN, low internal quantum efficiency (IQE) caused by large-lattice-mismatch heteroepitaxy, and strong quantum-confined Stark effect (QCSE), as well as the absorption by the nontransparent GaN contact layers. [15][16][17] A promising approach that dramatically improves the light output power is electron-beam (e-beam) pumping, especially for the short-wavelength UVC spectral range. [3,[18][19][20][21][22][23][24] This approach allows one to bypass the need for p-type or n-type injection layers and, thus, can largely increase the carrier injection efficiency. This provides a unique advantage over conventional LEDs at UVC range, since the p-type doping for high-Al-content AlGaN is High-output-power electron-beam (e-beam) pumped deep ultraviolet (DUV) light sources, operating at 230-270 nm, are achieved by adjusting the well thickness of binary ultrathin GaN/AlN multiple quantum wells. These structures are fabricated on high-quality thermally annealed AlN templates by metal-organic chemical vapor deposition. Owing to the reduced dislocation density, large electron-hole overlap, and efficient carrier injection by e-beam, the DUV light sources demonstrate high output powers of 24.8, 122.5, and 178.8 mW at central wavelengths of 232, 244, and 267 nm, respectively. Further growth optimization and employing an e-gun with increased beam current lead to a record output power of ≈2.2 W at emission wavelength of ≈260 nm, the key wavelength for water sterilization. This work manifests the practical levels of high-output-power DUV light sources operated by using e-beam pumping method. The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adom.201801763.Solid-state deep ultraviolet (DUV) optoelectronic devices in the spectral range of 200-280 nm, i.e., ultraviolet-C (UVC), have attracted much attention for their wide applications in sterilization, medical treatment, security, solar-blind photodetection, and so on. [1][2][3][4][5][6][7] Currently, Al(Ga)N material system is the most promising candidate for solid-state UVC light sources

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confidence: 99%

Deep Ultraviolet Light Source from Ultrathin GaN/AlN MQW Structures with Output Power Over 2 Watt

Wang

Rong

Иванов

et al. 2019

Advanced Optical Materials

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“…The internal quantum efficiency (IQE) can thus be largely improved for the acquired structures, which were grown by either metal‐organic vapor phase epitaxy (MOVPE) or molecular beam epitaxy (MBE) . However, the output power and emission efficiency of the mid‐ or deep‐UV light sources are still much poorer than those of blue light emitting diodes (LEDs) because they suffer from several inherent issues, in particular the transverse magnetic (TM, E // c ) polarized emission involvement, poor crystalline quality of the AlGaN active region, difficulty in p‐type doping for high‐Al‐content AlGaN layers, and inevitable light absorption in the commonly used p‐type GaN injection layers …”

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High‐Output‐Power Ultraviolet Light Source from Quasi‐2D GaN Quantum Structure

et al. 2016

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Quasi-2D GaN layers inserted in an AlGaN matrix are proposed as a novel active region to develop a high-output-power UV light source. Such a structure is successfully achieved by precise control in molecular beam epitaxy and shows an amazing output power of ≈160 mW at 285 nm with a pulsed electron-beam excitation. This device is promising and competitive in non-line-of-sight communications or the sterilization field.

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“…Many studies have reported strategies of defect reduction via substrate or template, [18][19][20] methods of high carrier connement, and hole injection. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] Low light extraction efficiency (LEE) is another challenge in achieving high efficiency for DUV LEDs. The LEE of the DUV LEDs has been improved by utilizing the ip-chip design, 36,37 a patterned sapphire substrate, 20,38 a patterned p-type layer, 39 and the nanowire structure.…”

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confidence: 99%

The influences of AlGaN barrier epitaxy in multiple quantum wells on the optoelectrical properties of AlGaN-based deep ultra-violet light-emitting diodes

et al. 2023

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Performance Improvements for AlGaN-Based Deep Ultraviolet Light-Emitting Diodes With the p-Type and Thickened Last Quantum Barrier

Cited by 42 publications

References 54 publications

Deep Ultraviolet Light Source from Ultrathin GaN/AlN MQW Structures with Output Power Over 2 Watt

Deep Ultraviolet Light Source from Ultrathin GaN/AlN MQW Structures with Output Power Over 2 Watt

High‐Output‐Power Ultraviolet Light Source from Quasi‐2D GaN Quantum Structure

The influences of AlGaN barrier epitaxy in multiple quantum wells on the optoelectrical properties of AlGaN-based deep ultra-violet light-emitting diodes

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