Extremely high internal quantum efficiency of AlGaN-based quantum wells on face-to-face annealed sputter-deposited AlN templates

Murotani, Hideaki; Fujii, Atsushi; Oshimura, Ryota; Kusaba, Takafumi; Uesugi, Kenjiro; Miyake, Hideto; Yamada, Yoichi

doi:10.35848/1882-0786/ac3802

Cited by 9 publications

(2 citation statements)

References 43 publications

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“…At 6 K, the PL efficiency is almost independent of the excitation power under both selective and non-selective excitation conditions. Therefore, we can assume that non-radiative recombination centers are inactive at 6 K in the measured excitation power range and the RRE is unity at LT. 15,16,20) Notably, in previous studies, the PL efficiency at LT changed as the excitation power was increased. 15,[21][22][23][24] This behavior indicates that in previous studies the RRE was not always unity at LT for all excitation power conditions.…”

Section: Methodsmentioning

confidence: 91%

Picosecond-laser-excited photoluminescence study of AlGaN quantum wells on epitaxially laterally overgrown AlN/sapphire under selective and non-selective excitation conditions

Tanaka

Ishii

Susilo

et al. 2022

Jpn. J. Appl. Phys.

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The radiative recombination efficiency (RRE) of AlGaN quantum wells on epitaxially laterally overgrown AlN/sapphire templates was investigated by picosecond-laser-excited photoluminescence (PL) spectroscopy under selective and non-selective excitation conditions. The PL efficiency, which was deduced by excitation-power-dependent PL measurements at low temperature (LT) and room temperature (RT), was unity at LT under both excitation conditions; However, at RT, the PL efficiency under non-selective excitation conditions was lower than that under selective excitation conditions. Time-resolved PL measurements revealed that, under non-selective excitation conditions, additional carriers are provided from the surrounding layers to the quantum-well layers, especially at LT. Therefore, at RT, the PL efficiency does not correspond to the RRE under non-selective excitation conditions. We propose a model to explain carrier dynamics under the two excitation conditions showing that the PL efficiency equals the RRE under selective excitation conditions.

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Section: Methodsmentioning

confidence: 91%

Picosecond-laser-excited photoluminescence study of AlGaN quantum wells on epitaxially laterally overgrown AlN/sapphire under selective and non-selective excitation conditions

Tanaka

Ishii

Susilo

et al. 2022

Jpn. J. Appl. Phys.

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“…Previously, we reported maximum IQE of 90% and 66% at room temperature (295 K) and 400 K, respectively from the 10 QWs on FFA Sp-AlN. 32) Actually, the detailed structure of the MQWs in this work is different from the previous one, we assume that the lower TDD and smoother surface morphology achieved in this work contributed to the higher IQE. Further, we speculate that the high EQE is owing to not only IQE but also to the improved current injection efficiency (CIE).…”

Section: -3mentioning

confidence: 52%

263 nm wavelength UV-C LED on face-to-face annealed sputter-deposited AlN with low screw- and mixed-type dislocation densities

Uesugi

Kuboya

Shojiki

et al. 2022

Appl. Phys. Express

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Regarding deep-ultraviolet optical device applications, face-to-face annealed sputter-deposited AlN (FFA Sp-AlN) is a promising alternative to the conventional metalorganic vapor phase epitaxy (MOVPE)-prepared AlN templates on sapphire substrates. However, FFA Sp-AlN tends to exhibit AlGaN growth-related hillock generation and surface morphology deterioration. In this study, we optimized the sputter-deposition conditions for AlN and MOVPE growth conditions for AlGaN to respectively reduce hillock density and size. After confirming AlGaN surface-flattening, we fabricated 263-nm-wavelength UV-C LEDs on the FFA Sp-AlN and achieved maximum external quantum efficiencies of approximately 4.9% and 8.0% without and with silicone encapsulation, respectively.

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Progress in Performance of AlGaN‐Based Ultraviolet Light Emitting Diodes

Lang,

Xu,

Wang

et al. 2024

Adv Elect Materials

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AlGaN‐based ultraviolet light‐emitting diodes (UV‐LEDs) have the advantages of mercury (Hg) pollution free, small size, high efficiency, and so on, and are widely used in military, medical, and industrial fields, which are considered to be the most promising alternative to the traditional Hg lamps. Great efforts are made over the past few decades to improve the device performance, thereby meeting the commercial production and application requirements of UV‐LEDs, which is always accompanied by a series of interesting physical topics. In this review, the recent research progress in performance of AlGaN‐based UV‐LEDs is summarized from the perspectives of electrical injection, electro‐optical conversion, and light extraction, which are responsible for the operation of devices. The detailed discussions include the major challenges, the corresponding technological breakthroughs, and also the outlook of material growth, energy band modulation, as well as device fabrication involved in UV‐LEDs, which are expected to be helpful for the thorough comprehension of device physics and further development of AlGaN‐based UV‐LEDs.

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Extremely high internal quantum efficiency of AlGaN-based quantum wells on face-to-face annealed sputter-deposited AlN templates

Cited by 9 publications

References 43 publications

Picosecond-laser-excited photoluminescence study of AlGaN quantum wells on epitaxially laterally overgrown AlN/sapphire under selective and non-selective excitation conditions

Picosecond-laser-excited photoluminescence study of AlGaN quantum wells on epitaxially laterally overgrown AlN/sapphire under selective and non-selective excitation conditions

263 nm wavelength UV-C LED on face-to-face annealed sputter-deposited AlN with low screw- and mixed-type dislocation densities

Progress in Performance of AlGaN‐Based Ultraviolet Light Emitting Diodes

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