Enhanced device performance of GaInN‐based deep green light emitting diodes with V‐defect‐free active region

Detchprohm, Theeradetch; Zhu, Mingwei; Zhao, Wei; Wang, Y.; Li, Y.; Xia, Yong; Wetzel, Christian

doi:10.1002/pssc.200880800

Cited by 17 publications

(12 citation statements)

References 8 publications

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“…[16][17][18][19] However, the output powers at high injection current of these devices currently do not outperform the best devices grown on (0001) planes (c-planes). 2,14,20,21 …”

Section: Introductionmentioning

confidence: 99%

Enhancement of efficiency of InGaN-based light emitting diodes through strain and piezoelectric field management

Pal

Migliorato

et al. 2013

Journal of Applied Physics

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We report calculations of the strain dependence of the piezoelectric field within InGaN multi-quantum wells light emitting diodes. Such fields are well known to be a strong limiting factor of the device performance. By taking into account the nonlinear piezoelectric coefficients, which in particular cases predict opposite trends compared to the commonly used linear coefficients, a significant improvement of the spontaneous emission rate can be achieved as a result of a reduction of the internal field. We propose that such reduction of the field can be obtained by including a metamorphic InGaN layer below the multiple quantum well active region. © 2013 AIP Publishing LLC

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“…[16][17][18][19] However, the output powers at high injection current of these devices currently do not outperform the best devices grown on (0001) planes (c-planes). 2,14,20,21 …”

Section: Introductionmentioning

confidence: 99%

Enhancement of efficiency of InGaN-based light emitting diodes through strain and piezoelectric field management

Pal

Migliorato

et al. 2013

Journal of Applied Physics

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“…LEDs emitting in the green spectrum currently have attained a record 40% internal efficiency. 2 Although it is an incredible statistic, it also indicates that there is still need for improvement. Nanowires offer a method of growing material with a high indium content free of strain related defects on a wider choice of substrates.…”

mentioning

confidence: 98%

Green luminescence of InGaN nanowires grown on silicon substrates by molecular beam epitaxy

Goodman

Protasenko

Verma

et al. 2011

Journal of Applied Physics

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Indium gallium nitride nanowires show promise as being prime candidates for optical devices since they can be grown with band gaps spanning the visible spectra, while at the same time can be composed of stress free material. The goal of the work presented here was to obtain InGaN nanowires producing green emission at room temperature. Two growth recipes were found to yield InGaN nanowire growth on silicon substrates using plasma-assisted molecular beam epitaxy. At room temperature the photoluminescence (PL) of wire ensembles indeed peaked at 530 nm but, in addition, it was discovered that at low temperatures the emission often covered a broader (360–700 nm) spectrum. This broad optical range indicated indium content fluctuations in individual wires, wire-to-wire fluctuations, or a combination of the two. EDX measurements performed on single wires confirmed this hypothesis and correlated well with PL data. Low temperature PL studies of InGaN individual wires also revealed interwire and intrawire inhomogeneity of emission spectra stemming from a nonuniform indium distribution. The emission quantum yield for bright single wires was extracted to be more than 50% at 4 K. The findings suggest that the wire surfaces do not efficiently quench optical emission at low temperatures. These defect-free wires offer not only a potential path for green emitters, but also as integrated phosphors for broad spectral emission.

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“…Common to all, in sequence of growth, is a 2 lm thick n-GaN, 2.5 nm thick unintentionally doped GaInN QWs separated by 20 nm thick GaN barriers, 20 nm thick p-AlGaN, and 200 nm thick p-GaN layers. 17 The number of GaInN/GaN QWs was varied to 8, 25, and 40. By help of an x-ray diffraction analysis of the (0002) superlattice fringes, an InN-fraction x ¼ 0.08 þ/À 0.01 was determined for the Ga 1Àx In x N layers.…”

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confidence: 99%

High 400 °C operation temperature blue spectrum concentration solar junction in GaInN/GaN

Zhao

Detchprohm

Wetzel

2014

Applied Physics Letters

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Transparent wide gap junctions suitable as high temperature, high flux topping cells have been achieved in GaInN/GaN by metal-organic vapor phase epitaxy. In structures of 25 quantum wells (QWs) under AM1.5G illumination, an open circuit voltage of 2.1 V is achieved. Of the photons absorbed in the limited spectral range of <450 nm, 64.2% are converted to electrons collected at the contacts under zero bias. At a fill factor of 45%, they account for a power conversion efficiency of38.6%. Under concentration, the maximum output power density per sun increases from 0.49 mW/cm2 to 0.51 mW/cm2 at 40 suns and then falls 0.42 mW/cm2 at 150 suns. Under external heating, a maximum of 0.59 mW/cm2 is reached at 250 °C. Even at 400 °C, the device is fully operational and exceeds room temperature performance. A defect analysis suggests that significantly higher fill factors and extension into longer wavelength ranges are possible with further development. The results prove GaInN/GaN QW solar junctions a viable and rugged topping cell for concentrator photovoltaics with minimal cooling requirements. By capturing the short range spectrum, they reduce the thermal load to any conventional cells stacked behind.

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Enhanced device performance of GaInN‐based deep green light emitting diodes with V‐defect‐free active region

Cited by 17 publications

References 8 publications

Enhancement of efficiency of InGaN-based light emitting diodes through strain and piezoelectric field management

Enhancement of efficiency of InGaN-based light emitting diodes through strain and piezoelectric field management

Green luminescence of InGaN nanowires grown on silicon substrates by molecular beam epitaxy

High 400 °C operation temperature blue spectrum concentration solar junction in GaInN/GaN

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