Synchrotron X-ray Topography Studies of Epitaxial Lateral Overgrowth of GaN on Sapphire

ABSTRACTSynchrotron white beam x-ray topography techniques, in section and large-area transmission modes, have been applied to the evaluation of ELOG GaN on A12O3. Using the openings in 100 nm thick SiO2 windows, a new GaN growth took place, which resulted in typical overgrowth thicknesses of 6.8 μm. Measurements on the recorded Laue patterns indicate that the misorientation of GaN with respect to the sapphire substrate (excluding a 30° rotation between them) varies considerably along various crystalline directions, reaching a maximum of a ∼0.66° rotation of the (0001) plane about the [01•1] axis. This is ∼3% smaller than the misorientation measured in the non-ELOG reference, which reached a maximum of 0.68°. This misorientation varies measurably as the stripe or window dimensions are changed. The quality of the ELOG epilayers is improved when compared to the non- ELOG samples, though some local deviations from lattice coherence were observed. Long range and large-scale (order of 100 μm long) strain structures were observed in all multi quantum well epilayers.

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Optical Properties of MBE Grown Cubic AlGaN Epilayers and AlGaN/GaN Quantum Well Structures

MRS Proceedings ◽

10.1557/proc-639-g5.9 ◽

2000 ◽

Vol 639 ◽

Cited By ~ 2

Author(s):

D.J. As ◽

T. Frey ◽

M. Bartels ◽

A. Khartchenko ◽

D. Schikora ◽

...

Keyword(s):

Optical Properties ◽

Quantum Well ◽

Linear Increase ◽

X Ray Diffraction ◽

Quantum Well Structures ◽

X Ray ◽

Al Content ◽

Frequency Plasma ◽

Multi Quantum Well

ABSTRACTCubic AlyGa1−yN/GaN heterostructures on GaAs(001) substrates were grown by radio-frequency plasma-assisted molecular beam epitaxy. High resolution X-ray diffraction, spectroscopic ellipsometry and cathodoluminescence were used to characterize the structural and optical properties of the alloy epilayers. X-ray diffraction reciprocal space maps demonstrate the good crystal quality of the cubic AlyGa1−yN films. Both SE as well as room temperature CL of the AlyGa1−yN epilayer show a linear increase of the band gap with increasing Al-content. A pseudomorphically strained cubic 10 × (2.4 nm GaN/ 4.8 nm Al0.12Ga0.88N) multi-quantum well (MQW) structure has been realized. Cathodoluminescence clearly demonstrates strong radiative recombination due to quantized states in the GaN well layer at a photon energy of 3.323 eV.

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Surface emitting 15 µm multi-quantum well LED on epitaxial lateral overgrowth InP/Si

Optical Materials Express ◽

10.1364/ome.395249 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1714 ◽

Cited By ~ 1

Author(s):

Giriprasanth Omanakuttan ◽

Yan-Ting Sun ◽

Carl Reuterskiöld Hedlund ◽

Carl Junesand ◽

Richard Schatz ◽

...

Keyword(s):

Quantum Well ◽

Epitaxial Lateral Overgrowth ◽

Lateral Overgrowth ◽

Multi Quantum Well

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Investigation on Epitaxial Lateral Overgrowth of InGaN/GaN Multi-Quantum-Well Nanowires

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2013.6071 ◽

2013 ◽

Vol 13 (2) ◽

pp. 1389-1391

Author(s):

Yao Yin ◽

Huabin Sun ◽

Xi Tang ◽

Ruihua Cao ◽

Peng Chen ◽

...

Keyword(s):

Quantum Well ◽

Epitaxial Lateral Overgrowth ◽

Lateral Overgrowth ◽

Multi Quantum Well

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Characteristics of Fielo-GaN Grown by Hydride Vapor Phase Epitaxy

MRS Proceedings ◽

10.1557/proc-639-g5.6 ◽

2000 ◽

Vol 639 ◽

Cited By ~ 4

Author(s):

Akira Usui ◽

Haruo Sunakawa ◽

Kenji Kobayashi ◽

Heiji Watanabe ◽

Masashi Mizuta

Keyword(s):

Electron Microscopy ◽

Dislocation Density ◽

Hydride Vapor Phase Epitaxy ◽

Epitaxial Lateral Overgrowth ◽

Rocking Curve ◽

X Ray ◽

Lateral Overgrowth ◽

Dislocation Behavior ◽

Reflection Electron Microscopy

ABSTRACTThe crystal quality of facet-initiated epitaxial lateral overgrowth (FIELO) -GaN, in particular, that in the vicinity of the GaN surface, is reported. It is shown that the surface smoothness of FIELO-GaN enables us to use it as an “epi-ready” substrate. The crystallinity of FIELO-GaN is evaluated by x-ray rocking curve (XRC) measurements. We indicate that the FWHM of XRC should be reduced with the decrease of the dislocation density. We previously reported that the dislocation behavior of FIELO-GaN causes the tilting of the c-axis in the overgrown regions. By using scanning reflection electron microscopy (SREM), however, we show that the tilting on the surface of thick FIELO-GaN was negligibly small.

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Design and Demonstration of Large Scale Cu2O Photocathodes with Metal Grid Structure for Photoelectrochemical Water Splitting

Energies ◽

10.3390/en14217422 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7422

Author(s):

Min-Kyu Son

Keyword(s):

Water Splitting ◽

Large Scale ◽

Grid Structure ◽

Large Area ◽

Intrinsic Conductivity ◽

Metal Grid ◽

Splitting System ◽

Insight Into ◽

Better Than

Upscaling of photoelectrode for a practical photoelectrochemical (PEC) water splitting system is still challenging because the PEC performance of large-scale photoelectrode is significantly low, compared to the lab scale photoelectrode. In an effort to overcome this challenge, sputtered gold (Au) and copper (Cu) grid lines were introduced to improve the PEC performance of large-scale cuprous oxide (Cu2O) photocathode in this work. It was demonstrated that Cu grid lines are more effective than Au grid lines to improve the PEC performance of large-scale Cu2O photocathode because its intrinsic conductivity and quality of grid lines are better than ones containing Au grid lines. As a result, the PEC performance of a 25-cm2 scaled Cu2O photocathode with Cu grid lines was almost double than one without grid lines, resulting in an improved charge transport in the large area substrate by Cu grid lines. Finally, a 50-cm2 scaled Cu2O photocathode with Cu grid lines was tested in an outdoor condition under natural sun. This is the first outdoor PEC demonstration of large-scale Cu2O photocathode with Cu grid lines, which gives insight into the development of efficient upscaled PEC photoelectrode.

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Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

Journal of Semiconductors ◽

10.1088/1674-4926/42/12/122804 ◽

2021 ◽

Vol 42 (12) ◽

pp. 122804

Author(s):

Shangfeng Liu ◽

Ye Yuan ◽

Shanshan Sheng ◽

Tao Wang ◽

Jin Zhang ◽

...

Keyword(s):

High Temperature ◽

Vapor Deposition ◽

Physical Vapor Deposition ◽

Flat Surface ◽

Epitaxial Lateral Overgrowth ◽

High Temperature Annealing ◽

High Quality ◽

High Crystalline Quality ◽

X Ray ◽

Lateral Overgrowth

Abstract In this work, based on physical vapor deposition and high-temperature annealing (HTA), the 4-inch crack-free high-quality AlN template is initialized. Benefiting from the crystal recrystallization during the HTA process, the FWHMs of X-ray rocking curves for (002) and (102) planes are encouragingly decreased to 62 and 282 arcsec, respectively. On such an AlN template, an ultra-thin AlN with a thickness of ~700 nm grown by MOCVD shows good quality, thus avoiding the epitaxial lateral overgrowth (ELOG) process in which 3–4 μm AlN is essential to obtain the flat surface and high crystalline quality. The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED, therefore significantly improving yields and decreasing cost.

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Large area deep ultraviolet light of Al0.47Ga0.53N/Al0.56Ga0.44N multi quantum well with carbon nanotube electron beam pumping

AIP Advances ◽

10.1063/1.5109956 ◽

2019 ◽

Vol 9 (7) ◽

pp. 075104 ◽

Cited By ~ 1

Author(s):

Sung Tae Yoo ◽

Byeongchan So ◽

Hye In Lee ◽

Okhyun Nam ◽

Kyu Chang Park

Keyword(s):

Electron Beam ◽

Carbon Nanotube ◽

Quantum Well ◽

Ultraviolet Light ◽

Large Area ◽

Deep Ultraviolet ◽

Multi Quantum Well

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Investigation of epitaxial lateral overgrowth by x‐ray topography

Journal of Applied Physics ◽

10.1063/1.351868 ◽

1992 ◽

Vol 72 (2) ◽

pp. 405-409 ◽

Cited By ~ 3

Author(s):

R. Köhler ◽

B. Jenichen ◽

E. Bauser ◽

R. Bergmann

Keyword(s):

Epitaxial Lateral Overgrowth ◽

X Ray ◽

Lateral Overgrowth

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ION BEAM LITHOGRAPHY AND NANOFABRICATION: A REVIEW

International Journal of Nanoscience ◽

10.1142/s0219581x05003139 ◽

2005 ◽

Vol 04 (03) ◽

pp. 269-286 ◽

Cited By ~ 181

Author(s):

F. WATT ◽

A. A. BETTIOL ◽

J. A. VAN KAN ◽

E. J. TEO ◽

M. B. H. BREESE

Keyword(s):

Mass Production ◽

Large Scale ◽

Focused Ion Beam ◽

Extreme Ultraviolet ◽

Ion Beam ◽

Large Area ◽

Near Surface ◽

X Ray ◽

Projection Lithography ◽

New Generation

To overcome the diffraction constraints of traditional optical lithography, the next generation lithographies (NGLs) will utilize any one or more of EUV (extreme ultraviolet), X-ray, electron or ion beam technologies to produce sub-100 nm features. Perhaps the most under-developed and under-rated is the utilization of ions for lithographic purposes. All three ion beam techniques, FIB (Focused Ion Beam), Proton Beam Writing (p-beam writing) and Ion Projection Lithography (IPL) have now breached the technologically difficult 100 nm barrier, and are now capable of fabricating structures at the nanoscale. FIB, p-beam writing and IPL have the flexibility and potential to become leading contenders as NGLs. The three ion beam techniques have widely different attributes, and as such have their own strengths, niche areas and application areas. The physical principles underlying ion beam interactions with materials are described, together with a comparison with other lithographic techniques (electron beam writing and EUV/X-ray lithography). IPL follows the traditional lines of lithography, utilizing large area masks through which a pattern is replicated in resist material which can be used to modify the near-surface properties. In IPL, the complete absence of diffraction effects coupled with ability to tailor the depth of ion penetration to suit the resist thickness or the depth of modification are prime characteristics of this technique, as is the ability to pattern a large area in a single brief irradiation exposure without any wet processing steps. p-beam writing and FIB are direct write (maskless) processes, which for a long time have been considered too slow for mass production. However, these two techniques may have some distinct advantages when used in combination with nanoimprinting and pattern transfer. FIB can produce master stamps in any material, and p-beam writing is ideal for producing three-dimensional high-aspect ratio metallic stamps of precise geometry. The transfer of large scale patterns using nanoimprinting represents a technique of high potential for the mass production of a new generation of high area, high density, low dimensional structures. Finally a cross section of applications are chosen to demonstrate the potential of these new generation ion beam nanolithographies.

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