High-Power Blue-Violet Semipolar ($20\bar{2}\bar{1}$) InGaN/GaN Light-Emitting Diodes with Low Efficiency Droop at 200 A/cm$^{2}$

Zhao, Yuji; Tanaka, Shinichi; Pan, Chih-Chien; Fujito, Kenji; Feezell, Daniel; Speck, James S.; DenBaars, Steven P.; Nakamura, Shuji

doi:10.1143/apex.4.082104

Cited by 201 publications

(194 citation statements)

References 22 publications

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“…Besides, (1122) oriented films appear to be mostly smooth [9]. Effective long-wavelength emission of InGaN/GaN LEDs grown on the (2021) substrate and on the (2021) substrate has been reported in many papers (see, e.g., [17][18][19] and [20][21][22], respectively). However, taking into account aggregate results of the above analysis, we have decided to choose the (1122) InGaN/GaN LEDs.…”

Section: Designing Of Nitride Leds With Reduced Polarization Effectsmentioning

confidence: 97%

A method used to overcome polarization effects in semi-polar structures of nitride light-emitting diodes emitting green radiation

2013

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Polarization effects are studied within nitride light-emitting diodes (LEDs) manufactured on standard polar and semipolar substrates. A new theoretical approach, somewhat different than standard ones, is proposed to this end. It is well known that when regular polar GaN substrates are used, strong piezoelectric and spontaneous polarizations create built-in electric fields leading to the quantumconfined Stark effects (QCSEs). These effects may be completely avoided in nonpolar crystallographic orientations, but then there are problems with manufacturing InGaN layers of relatively high Indium contents necessary for the green emission. Hence, a procedure leading to partly overcoming these polarization problems in semi-polar LEDs emitting green radiation is proposed. The (1122) crystallographic substrate orientation (inclination angle of 58 • to c plane) seems to be the most promising because it is characterized by low Miller-Bravais indices leading to highquality and high Indium content smooth growth planes. Besides, it makes possible an increased Indium incorporation efficiency and it is efficient in suppressing QCSE. The In 0.3 Ga 0.7 N/GaN QW LED grown on the semipolar (1122) substrate has been found as currently the optimal LED structure emitting green radiation.

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Section: Designing Of Nitride Leds With Reduced Polarization Effectsmentioning

confidence: 97%

A method used to overcome polarization effects in semi-polar structures of nitride light-emitting diodes emitting green radiation

2013

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“…Also the intrinsic field leads to a spatial separation of electron and hole wave functions, causing a reduced radiative recombination rate [4,6], an effect that can be particularly undesirable for high-efficiency optoelectronic devices. To circumvent these effects arising from the intrinsic built-in fields, which fundamentally are caused by the growth along the polar c axis, significant research has been directed towards the fabrication of semi-and nonpolar structures [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In the case of semi-and nonpolar planes the c axis is at a nonvanishing angle with respect to the growth direction.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of semi-and nonpolar planes the c axis is at a nonvanishing angle with respect to the growth direction. In semipolar planes residual built-in fields are expected and observed, even though these fields are significantly reduced [15,18]. In terms of built-in field reduction, nonpolar QW systems are ideal since in these structures the c axis lies in the growth plane.…”

Section: Introductionmentioning

confidence: 99%

Structural, electronic, and optical properties ofm-plane InGaN/GaN quantum wells: Insights from experiment and atomistic theory

Schulz¹,

Tanner

O’Reilly

et al. 2015

Phys. Rev. B

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In this paper we present a detailed analysis of the structural, electronic, and optical properties of an m-plane (In,Ga)N/GaN quantum well structure grown by metal organic vapor phase epitaxy. The sample has been structurally characterized by x-ray diffraction, scanning transmission electron microscopy, and 3D atom probe tomography. The optical properties of the sample have been studied by photoluminescence (PL), time-resolved PL spectroscopy, and polarized PL excitation spectroscopy. The PL spectrum consisted of a very broad PL line with a high degree of optical linear polarization. To understand the optical properties we have performed atomistic tight-binding calculations, and based on our initial atom probe tomography data, the model includes the effects of strain and built-in field variations arising from random alloy fluctuations. Furthermore, we included Coulomb effects in the calculations. Our microscopic theoretical description reveals strong hole wave function localization effects due to random alloy fluctuations, resulting in strong variations in ground state energies and consequently the corresponding transition energies. This is consistent with the experimentally observed broad PL peak. Furthermore, when including Coulomb contributions in the calculations we find strong exciton localization effects which explain the form of the PL decay transients. Additionally, the theoretical results confirm the experimentally observed high degree of optical linear polarization. Overall, the theoretical data are in very good agreement with the experimental findings, highlighting the strong impact of the microscopic alloy structure on the optoelectronic properties of these systems.

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“…In addition, it allows to explore (001) oriented cubic SiC surfaces as needed for further heteroepitaxial growth of other cubic semiconductors. For example, the growth of cubic gallium nitride would be very beneficial to explore the more efficient white light emitting diodes due to less influence of the droop effect [9,10].…”

Section: Introductionmentioning

confidence: 99%

Sublimation growth of thick freestanding 3C-SiC using CVD-templates on silicon as seeds

et al. 2012

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Abstract:Cubic silicon carbide is a promising material for medium power electronics operating at high frequencies and for the subsequent growth of gallium nitride for more efficient light emitting diodes. We present a new approach to produce freestanding cubic silicon carbide (3C-SiC) with the ability to obtain good crystalline quality regarding increased domain size and reduced defect density. This would pave the way to achieve substrates of 3C-SiC so that the applications of cubic silicon carbide material having selectively (111) or (001) oriented surfaces can be explored. Our method is based on the combination of the chemical vapor deposition method and the fast sublimation growth process. Thin layers of cubic silicon carbide grown heteroepitaxially on silicon substrates are for the first time used for a subsequent sublimation growth step to increase layer thicknesses. We have been able to realize growth of freestanding (001) oriented 3C-SiC substrates using growth rates around 120 µm/h and diameters of more than ten millimeters. The structural quality from XRD rocking curve measurements of (001) oriented layers shows good FWHM values down to 78 arcsec measured over an area of 1x2 mm 2 , which is a quality improvement of 2-3 times compared with other methods like CVD.

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High-Power Blue-Violet Semipolar ($20\bar{2}\bar{1}$) InGaN/GaN Light-Emitting Diodes with Low Efficiency Droop at 200 A/cm$^{2}$

Cited by 201 publications

References 22 publications

A method used to overcome polarization effects in semi-polar structures of nitride light-emitting diodes emitting green radiation

A method used to overcome polarization effects in semi-polar structures of nitride light-emitting diodes emitting green radiation

Structural, electronic, and optical properties ofm-plane InGaN/GaN quantum wells: Insights from experiment and atomistic theory

Sublimation growth of thick freestanding 3C-SiC using CVD-templates on silicon as seeds

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