Optical Investigations and Absorption Coefficient Determination of InGaN/GaN Quantum Wells

Kvietkova, J.; Siozade, Laure; Disseix, P.; Vasson, A.; Leymarie, J.; Damilano, B.; Grandjean, N.; Massies, J.

doi:10.1002/1521-396x(200203)190:1<135::aid-pssa135>3.0.co;2-1

Cited by 14 publications

(6 citation statements)

References 14 publications

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“…. The quantum well loss is normally small as absorption in the c ‐plane quantum wells is relatively low (∼500 cm −1 ) due to the large Stokes shift created by the strong polarization fields within the quantum wells . There is also optical loss in the p‐type GaN layers, but because the p‐layer is thin and the absorption coefficient within that layer is relatively low (<10 cm −1 ), this loss is small too.…”

Section: State‐of‐the‐art Power‐conversion Efficiencies: Blue Ledsmentioning

confidence: 99%

Comparison between blue lasers and light‐emitting diodes for future solid‐state lighting

Wierer

Tsao

Sizov

2013

Laser & Photonics Reviews

492

244

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Solid‐state lighting (SSL) is now the most efficient source of high color quality white light ever created. Nevertheless, the blue InGaN light‐emitting diodes (LEDs) that are the light engine of SSL still have significant performance limitations. Foremost among these is the decrease in efficiency at high input current densities widely known as “efficiency droop.” Efficiency droop limits input power densities, contrary to the desire to produce more photons per unit LED chip area and to make SSL more affordable. Pending a solution to efficiency droop, an alternative device could be a blue laser diode (LD). LDs, operated in stimulated emission, can have high efficiencies at much higher input power densities than LEDs can. In this article, LEDs and LDs for future SSL are explored by comparing: their current state‐of‐the‐art input‐power‐density‐dependent power‐conversion efficiencies; potential improvements both in their peak power‐conversion efficiencies and in the input power densities at which those efficiencies peak; and their economics for practical SSL.

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Section: State‐of‐the‐art Power‐conversion Efficiencies: Blue Ledsmentioning

confidence: 99%

Comparison between blue lasers and light‐emitting diodes for future solid‐state lighting

Wierer

Tsao

Sizov

2013

Laser & Photonics Reviews

492

244

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“…An input current of 120 mA is used and the chip (24 × 24 mil in size) has a dominant wavelength of 450 nm. Absorption coefficients for the GaN and the MQW are 200 cm-1 and 3600 cm-1, respectively [10,11]. For the BR-based chip, commercially available LED chips with two different BR materials are selected: the BR with the [12].…”

Section: Methodsmentioning

confidence: 99%

Optical role of die attach adhesive for white LED emitters: light output enhancement without chip-level reflectors

Kim

Shih

You³

et al. 2015

J Sol State Light

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A thin optical reflector is often introduced to the backside of the standard mesa type light emitting diode (LED) chip with the aim to enhance its light output. However, most of the reported light output enhancements because of backside reflector (BR) introduction might not be relevant. This is because the reported measurement is often from a naked LED chip instead of a packaged LED emitter, and those based on the packaged emitters employing conventional silver based die attach adhesive (DAA). The actual role of BR, which is expected to be greatly influenced by the packaging materials and processes, is investigated for the monotonic blue color and white LED emitters using Monte-Carlo simulations. Contrary to prior reports, it is demonstrated for the first time that the role of BR can be diminished when the optically transparent DAA is used and other key packaging materials and processes are optimized, i.e., the light output for a packaged emitter with a BR-free chip can be as high as that of the packaged emitter using the same chip but with an added BR.

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“…(9) will be too low. We summarized the photoluminescence excitation data and measurement results from recent studies [44][45][46][47][48], and revised Eq. (9) to be Boltzmann form:…”

Section: Absorptions Of Blue Led Materialsmentioning

confidence: 99%

Precise optical modeling of blue light-emitting diodes by Monte Carlo ray-tracing

Liu¹,

Wang²,

Luo³

et al. 2010

Opt. Express

119

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Precise optical modeling of blue light-emitting diodes (LEDs) is constructed by reasonable optical parameters and Monte Carlo ray-tracing with the capability of precisely predicting light extraction and radiation pattern for both bare LED and packaged LED. Refractive indices and absorption coefficients of LED materials are determined by abundant references and comparisons between simulations and experiments. Surface roughness is considered in the optical model to improve the simulation precision. The simulation precisions are excellent for both bare blue LEDs (>96.5% for light extraction and >99% for radiation pattern) and packaged blue LEDs (>98.5% for both light extraction and radiation pattern).

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Optical Investigations and Absorption Coefficient Determination of InGaN/GaN Quantum Wells

Cited by 14 publications

References 14 publications

Comparison between blue lasers and light‐emitting diodes for future solid‐state lighting

Comparison between blue lasers and light‐emitting diodes for future solid‐state lighting

Optical role of die attach adhesive for white LED emitters: light output enhancement without chip-level reflectors

Precise optical modeling of blue light-emitting diodes by Monte Carlo ray-tracing

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