High-Brightness InGaN Blue, Green and Yellow Light-Emitting Diodes with Quantum Well Structures

Nakamura, Shuji; Senoh, Masayuki; Iwasa, Naruhito; Nagahama, Shin–ichi

doi:10.1143/jjap.34.l797

Cited by 1,469 publications

(672 citation statements)

References 13 publications

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“…[1][2][3] Carrier dynamics in such device structures are beginning to be understood through the use of high power, short pulse, regenerative and optical parametric amplifiers. [4][5][6][7] In this paper, stimulated emission (SE) in InGaN multiple quantum well (MQW) laser structures with differing QW depths is explored.…”

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confidence: 99%

Stimulated emission and ultrafast carrier relaxation in InGaN multiple quantum wells

Özgür

Everitt

Keller

et al. 2003

Applied Physics Letters

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Stimulated emission (SE) was measured from two InGaN multiple quantum well (MQW) laser structures with different In compositions. SE threshold power densities (I th ) increased with increasing QW depth (x). Time-resolved differential transmission measurements mapped the carrier relaxation mechanisms and explained the dependence of I th on x. Carriers are captured from the barriers to the QWs in < 1 ps, while carrier recombination rates increased with increasing x. For excitation above I th an additional, fast relaxation mechanism appears due to the loss of carriers in the barriers through a cascaded refilling of the QW state undergoing SE. The increased material inhomogeneity with increasing x provides additional relaxation channels outside the cascaded refilling process, removing carriers from the SE process and increasing I th . 78.47.+p,78.66.Fd,78.45.+h,78.67.De Recent advances in the growth of group-III nitride heterostructures have made it possible to manufacture efficient green, blue, and ultraviolet emitters and detectors. [1][2][3] Carrier dynamics in such device structures are beginning to be understood through the use of high power, short pulse, regenerative and optical parametric amplifiers. [4][5][6][7] In this paper, stimulated emission (SE) in InGaN multiple quantum well (MQW) laser structures with differing QW depths is explored. SE threshold power densities increase with increasing QW depth, and ultrafast measurements of carrier dynamics reveal why.Two different InGaN MQW samples, differing primarily by QW In composition (x), were grown on c-plane sapphire in a modified two flow metalorganic chemical vapor deposition (MOCVD) reactor. 8 Both samples have ∼2 µm thick GaN:Si base layers. The 12% sample consists of 10 periods of 8.2 nm/3.4 nm In 0.07 Ga 0.93 N:Si/In 0.12 Ga 0.88 N QWs and is capped with a 100 nm thick GaN:Si layer. The 23% sample consists of 12 periods of 10 nm/3.5 nm In 0.03 Ga 0.97 N:Si/In 0.23 Ga 0.77 N QWs and is capped with 16 nm thick Al 0.10 Ga 0.90 N and 40 nm thick GaN:Si layers. The In compositions and the QW/barrier thicknesses are determined by high resolution X-Ray measurements. Material inhomogeneities, which arise from QW thickness fluctuations, compositional fluctuations, and In phase separation, have previously been observed to increase with increasing x and will be shown to play an important role in carrier relaxation and emission processes. 9,10 Fig. 1 shows the cw-PL for 3.81 eV low intensity (300W Xe lamp) and moderate intensity (25mW HeCd laser at 325 nm) excitations, and time-integrated PL (TI-PL) with a high intensity (∼15 µJ/cm 2 ) pulsed 3.31 eV excitation for both MQW samples. PL for the 12% sample shows a single peak at 3.01 eV for both Xe lamp (not shown) and HeCd excitations. The 23% sample shows at least two well-defined PL peaks for Xe-Lamp and HeCd laser excitation, the higher energy of which (2.52 eV) is assigned as the main PL from the QWs. The lower energy PL peak is associated with impurity (yellow) emission. For both samples, TI-PL from spont...

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confidence: 99%

Stimulated emission and ultrafast carrier relaxation in InGaN multiple quantum wells

Özgür

Everitt

Keller

et al. 2003

Applied Physics Letters

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“…Similar to previous reports, we find that the polarization field accounts for the promotion of ballistic or quasi-ballistic transport, or carrier leakage. In some publications, 21,22 the dependence of luminescence efficiency on In composition of the quantum well was observed, and the difference in polarization field was hypothesized to be the main cause. Nevertheless, as showed in Fig.…”

Section: Discussionmentioning

confidence: 99%

Overshoot effects of electron on efficiency droop in InGaN/GaN MQW light-emitting diodes

Huang

Liu

et al. 2016

AIP Advances

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To evaluate electron leakage in InGaN/GaN multiple quantum well (MQW) light emitting diodes (LEDs), analytic models of ballistic and quasi-ballistic transport are developed. With this model, the impact of critical variables effecting electron leakage, including the electron blocking layer (EBL), structure of multiple quantum wells (MQWs), polarization field, and temperature are explored. The simulated results based on this model shed light on previously reported experimental observations and provide basic criteria for suppressing electron leakage, advancing the design of InGaN/GaN LEDs.

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“…InGaN LEDs are attractive for optogenetic applications because the emission wavelength can be tailored for the activation of common opsins 172 . GaN-based LEDs are most commonly grown on sapphire or SiC substrates for minimal lattice mismatch at the GaN-substrate interface 173 because this structure enables efficient electronto-photon conversion.…”

Section: Mems Led Integrated Probesmentioning

confidence: 99%

State-of-the-art MEMS and microsystem tools for brain research

et al. 2017

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Mapping brain activity has received growing worldwide interest because it is expected to improve disease treatment and allow for the development of important neuromorphic computational methods. MEMS and microsystems are expected to continue to offer new and exciting solutions to meet the need for high-density, high-fidelity neural interfaces. Herein, the state-of-the-art in recording and stimulation tools for brain research is reviewed, and some of the most significant technology trends shaping the field of neurotechnology are discussed.

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High-Brightness InGaN Blue, Green and Yellow Light-Emitting Diodes with Quantum Well Structures

Cited by 1,469 publications

References 13 publications

Stimulated emission and ultrafast carrier relaxation in InGaN multiple quantum wells

Stimulated emission and ultrafast carrier relaxation in InGaN multiple quantum wells

Overshoot effects of electron on efficiency droop in InGaN/GaN MQW light-emitting diodes

State-of-the-art MEMS and microsystem tools for brain research

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