Recent Progress in AlGaN Deep-UV LEDs

Hasegawa, Hideki

doi:10.5772/intechopen.79936

Cited by 16 publications

(12 citation statements)

References 57 publications

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“…Because dislocations are serious nonradiative centers in AlGaN, efforts on producing low dislocation density AlN templates on sapphire were essential in the initial stage of development. Recent work using a high reflectance p-metal contact with a transparent AlGaN p-layer has increased the demonstrated external quantum efficiency (EQE) at about 270 nm emission wavelength to 20% . Application of modern outcoupling technologies using photonic lattice concepts predicts a light extraction efficiency (LEE) up to 70% in the future .…”

Section: Iii-nitride Nanowire Materials and Devicesmentioning

confidence: 99%

“… A large effort is presently spent on developing UV LEDs , and lasers in the planar technology. LEDs may be produced in AlN, typically employing a superlattice concept for the active region to achieve the desired p-conductivity .…”

Section: Iii-nitride Nanowire Materials and Devicesmentioning

confidence: 99%

“…Recent work using a high reflectance p-metal contact with a transparent AlGaN p-layer has increased the demonstrated external quantum efficiency (EQE) at about 270 nm emission wavelength to 20%. 441 Application of modern outcoupling technologies using photonic lattice concepts predicts a light extraction efficiency (LEE) up to 70% in the future. 441 The light is then extracted from the backside of the LED structure.…”

Section: Chemical Reviewsmentioning

confidence: 99%

“…441 Application of modern outcoupling technologies using photonic lattice concepts predicts a light extraction efficiency (LEE) up to 70% in the future. 441 The light is then extracted from the backside of the LED structure.…”

Section: Chemical Reviewsmentioning

confidence: 99%

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Synthesis and Applications of III–V Nanowires

et al. 2019

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Low-dimensional semiconductor materials structures, where nanowires are needle-like one-dimensional examples, have developed into one of the most intensely studied fields of science and technology. The subarea described in this review is compound semiconductor nanowires, with the materials covered limited to III−V materials (like GaAs, InAs, GaP, InP,...) and III-nitride materials (GaN, InGaN, AlGaN,...). We review the way in which several innovative synthesis methods constitute the basis for the realization of highly controlled nanowires, and we combine this perspective with one of how the different families of nanowires can contribute to applications. One reason for the very intense research in this field is motivated by what they can offer to main-stream semiconductors, by which ultrahigh performing electronic (e.g., transistors) and photonic (e.g., photovoltaics, photodetectors or LEDs) technologies can be merged with silicon and CMOS. Other important aspects, also covered in the review, deals with synthesis methods that can lead to dramatic reduction of cost of fabrication and opportunities for up-scaling to mass production methods.

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Section: Iii-nitride Nanowire Materials and Devicesmentioning

confidence: 99%

Section: Iii-nitride Nanowire Materials and Devicesmentioning

confidence: 99%

Section: Chemical Reviewsmentioning

confidence: 99%

Section: Chemical Reviewsmentioning

confidence: 99%

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Synthesis and Applications of III–V Nanowires

et al. 2019

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“…In addition to the enormous advantages of LED technology over gas discharge lamps, such as higher efficiency and much longer life times, considerable health hazards and the detrimental environmental impact of the mercury-based UV light source are circumvented as well by switching to a UV LED technology. However, the total output performance of UV LEDs is currently limited by the low light extraction efficiency (LEE) due to a sizeable UV light absorption of the electrical contact layers . With the introduction of an efficient UV-transparent electrode material, UV LEDs would see a widespread use for the disinfection of water, sterilization of air and surfaces in hospitals, hotel rooms, and food packaging facilities, , and for counterfeit detection, high-density optical recording, and polymer curing .…”

Section: Introductionmentioning

confidence: 99%

Sputtered Sr_xNbO₃ as a UV-Transparent Conducting Film

Roth

Paul

Goldner

et al. 2020

ACS Appl. Mater. Interfaces

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Expanding the application space of transparent electrodes toward the ultraviolet range has been found challenging when utilizing the conventional approach to degenerately dope semiconductors with band gaps larger than ZnO or In2O3. Here, it is shown that the correlated metal Sr x NbO3 with x < 1 is ideally suited as a UV-transparent electrode material, enabling UV light-emitting diodes for a wide range of applications from water disinfection to polymer curing. It is demonstrated that Sr x NbO3 thin films can be grown by radio frequency (RF) sputtering and that they remain in the perovskite phase despite a sizeable Sr deficiency. The electrical and optical properties are characterized and compared to those of commonly used indium tin oxide (ITO) and Sn-doped Ga2O3 transparent conductor standards. Sr x NbO3 films were found to have sheet resistances as low as 30 Ω sq–1 with optical transmission at a wavelength of 280 nm up to 86%, marking a two-order-of-magnitude increase over the performance of traditional UV-transparent conductors. The compatibility of Sr x NbO3 with a physical vapor deposition technique that is widely employed in the transparent conductor coating industry along with the robustness of the highly electrically conducting and optically transparent perovskite phase makes it an ideal transparent electrode for applications in the UV spectrum.

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2D‐GaN/AlNMonolayer‐Thick Quantum Wells

Jmerik

2020

Digital Encyclopedia of Applied Physics

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The unique structural and optical properties of two‐dimensional (2D)‐GaN multiple quantum wells (MQWs) with a nominal thickness of 1.5–2 monolayers (MLs) in AlN barriers allow one to consider them as highly efficient electron‐beam pumped ultraviolet‐C (UVC) emitters. These structures grown by both plasma‐assisted molecular beam epitaxy (PA MBE) and metalorganic vapor‐phase epitaxy on standardc‐sapphire substrates demonstrate an output optical pulse power of 1 and 2.2 W at a wavelength of 240 and 260 nm, respectively. This article focuses on the PA MBE of 2D‐GaN/AlN MQW structures using metal‐rich conditions and relatively low substrate temperatures (∼700 °C), which ensure the step‐flow growth of all layers with precise control of their thickness and abrupt interfaces. The revealed high internal quantum efficiency up to 75% in the (1–2)ML‐thick GaN/AlN QWs formed under these conditions is explained not only by the suppression of quantum‐confined Stark effect and the absence of TE/TM polarization switching in binary few‐ML‐thick QWs, but also by an enhanced rate of the excitonic transitions that mainly determine radiative recombination in such ultra‐thin QWs. In addition, the unusual quasi‐stress‐free growth of 2D‐GaN/AlN MQW structures allowed to increase the number of QWs up to 360 with an active region thickness of ∼2 μm.

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Recent Progress in AlGaN Deep-UV LEDs

Cited by 16 publications

References 57 publications

Synthesis and Applications of III–V Nanowires

Synthesis and Applications of III–V Nanowires

Sputtered Sr_xNbO₃ as a UV-Transparent Conducting Film

2D‐GaN/AlNMonolayer‐Thick Quantum Wells

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Recent Progress in AlGaN Deep-UV LEDs

Cited by 16 publications

References 57 publications

Synthesis and Applications of III–V Nanowires

Synthesis and Applications of III–V Nanowires

Sputtered SrxNbO3 as a UV-Transparent Conducting Film

2D‐GaN/AlNMonolayer‐Thick Quantum Wells

Contact Info

Product

Resources

About

Sputtered Sr_xNbO₃ as a UV-Transparent Conducting Film