Color mixing from monolithically integrated InGaN-based light-emitting diodes by local strain engineering

Chung, Kunook; Sui, Jingyang; Demory, Brandon; Ku, Pei-Cheng

doi:10.1063/1.4995561

Cited by 38 publications

(31 citation statements)

References 22 publications

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“…The strain state of the In x Ga 1−x N QWs can cause a change in the bandgap energy E g and also of the internal piezoelectric field F. Indeed, strain relaxation at the mesa edges can cause a PL blue-shift of the In x Ga 1−x N QWs due to a reduction of the internal piezoelectric field. This last effect has been shown to have a significant impact for very small nanostructures: the PL emission of red-emitting In x Ga 1−x N QWs is shifted to green and blue when they are selectively etched to form nanowires with diameters of 150 and 50 nm, respectively 9 . In our work, the minimum mesa size is 10 µm and therefore a strong impact of strain variation on the In x Ga 1−x N bandgap and the piezoelectric field at the center of the mesas is not expected.…”

Section: Discussionmentioning

confidence: 99%

“…Mixing the three basic blue/green/red colors directly on the same wafer is therefore highly desirable and constitutes an important challenge. Efforts towards this objective have been reported in the literature using for example nanowires grown by molecular beam epitaxy 5 , 6 , light conversion by (Ga,In)N multiple quantum wells 7 , facets with different orientations 8 , and local etching of red-emitting LED structures 9 .…”

Section: Introductionmentioning

confidence: 99%

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Blue to yellow emission from (Ga,In)/GaN quantum wells grown on pixelated silicon substrate

Damilano¹,

Portail²,

Frayssinet³

et al. 2020

Sci Rep

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It is shown that substrate pixelisation before epitaxial growth can significantly impact the emission color of semiconductor heterostructures. The wavelength emission from InxGa1−xN/GaN quantum wells can be shifted from blue to yellow simply by reducing the mesa size from 90 × 90 µm2 to 10 × 10 µm2 of the patterned silicon used as the substrate. This color shift is mainly attributed to an increase of the quantum well thickness when the mesa size decreases. The color is also affected, in a lesser extent, by the trench width between the mesas. Cathodoluminescence hyperspectral imaging is used to map the wavelength emission of the InxGa1−xN/GaN quantum wells. Whatever the mesa size is, the wavelength emission is red-shifted at the mesa edges due to a larger quantum well thickness and In composition.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Blue to yellow emission from (Ga,In)/GaN quantum wells grown on pixelated silicon substrate

Damilano¹,

Portail²,

Frayssinet³

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…In this way, the pixels can be fabricated on the wafer enabling a monolithic approach. Growing all three colors have been successful with site‐controlled growth where the confinement defines how much indium is incorporated . This monolithic approach has been used to produce nanowires structures .…”

Section: Challenges and Solutionsmentioning

confidence: 99%

III‐Nitride Micro‐LEDs for Efficient Emissive Displays

Wierer

Tansu

2019

Laser & Photonics Reviews

119

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Emissive displays based on light‐emitting diodes (LEDs), with high pixel density, luminance, efficiency, and large color gamut, are of great interest for applications such as watches, phones, and virtual displays. The high pixel density requirements of some emissive displays require a particular class of LEDs that are sub‐20‐micrometers in length, called micro‐LEDs. While state‐of‐the‐art emissive displays incorporate organic LEDs, an alternative is inorganic III‐nitride LEDs with potential reliability and efficiency benefits. Here we explore the performance, challenges, and prospective outcomes for III‐nitride micro‐LEDs to produce efficient emissive displays and provide insight to advance this technology. Calculations are performed to determine the operating points for the micro‐LEDs and the efficiency of the overall emissive display. It is shown that III‐nitride micro‐LEDs suffer from some of the same problems as their larger‐sized solid‐state lighting LED cousins; however, the operating conditions of micro‐LEDs can result in different challenges and research efforts. These challenges include improving efficiency at low current densities; improving the efficiency of longer wavelength (green and red) LEDs; and creating device designs that can overcome low coupling efficiency, high surface recombination, and display assembly difficulties.

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“…Nevertheless, long-wavelength emission is difficult to achieve from GaInN/GaN multiple quantum well structures, owing to the degradation of crystalline quality and the large strain-induced piezoelectric field [17]. Recent studies have achieved different emission wavelengths from three-dimensional structures fabricated by local strain engineering [18][19][20]. Using the top-down etching method, the authors of reference [21] fabricated monolithic LEDs combining microstructure and nanostructures of GaInN/GaN, which emit distinctive blue-green-yellow light with a color rendering index (CRI) of 41.…”

Section: Introductionmentioning

confidence: 99%

Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD

Ito

Sone

et al. 2020

Nanomaterials

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Broadened emission was demonstrated in coaxial GaInN/GaN multiple quantum shell (MQS) nanowires that were monolithically grown by metalorganic chemical vapor deposition. The non-polar GaInN/GaN structures were coaxially grown on n-core nanowires with combinations of three different diameters and pitches. To broaden the emission band in these three nanowire patterns, we varied the triethylgallium (TEG) flow rate and the growth temperature of the quantum barriers and wells, and investigated their effects on the In incorporation rate during MQS growth. At higher TEG flow rates, the growth rate of MQS and the In incorporation rate were promoted, resulting in slightly higher cathodoluminescence (CL) intensity. An enhancement up to 2–3 times of CL intensity was observed by escalating the growth temperature of the quantum barriers to 800 °C. Furthermore, decreasing the growth temperature of the quantum wells redshifted the peak wavelength without reducing the MQS quality. Under the modified growth sequence, monolithically grown nanowires with a broaden emission was achieved. Moreover, it verified that reducing the filling factor (pitch) can further promote the In incorporation probability on the nanowires. Compared with the conventional film-based quantum well LEDs, the demonstrated monolithic coaxial GaInN/GaN nanowires are promising candidates for phosphor-free white and micro light-emitting diodes (LEDs).

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Color mixing from monolithically integrated InGaN-based light-emitting diodes by local strain engineering

Cited by 38 publications

References 22 publications

Blue to yellow emission from (Ga,In)/GaN quantum wells grown on pixelated silicon substrate

Blue to yellow emission from (Ga,In)/GaN quantum wells grown on pixelated silicon substrate

III‐Nitride Micro‐LEDs for Efficient Emissive Displays

Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD

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