Yukari Ishikawa

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cond-mat.mtrl-sci2026

Determination of Burgers-vector directions of threading edge dislocations in GaN by phase-contrast microscopy

Yukari Ishikawa, Maki Shimizu, Koji Sato +4

Phase-contrast microscopy enables rapid, nondestructive observation of threading dislocations in GaN, but the relationship between dislocation contrast and the Burgers vector has n…

cond-mat.mtrl-sci2026

Groove-shaped defects in as-grown (001)-oriented $β$ -Ga $_{2}$ O $_{3}$ epilayers prepared by halide vapor phase epitaxy

Yongzhao Yao, Daiki Katsube, Hirotaka Yamaguchi +1

Groove-shaped defects (GSDs) degrade the surface flatness of as-grown (001)-oriented $β$ -Ga $_{2}$ O $_{3}$ epilayers and necessitate chemical mechanical polishing before device fabricati…

cond-mat.mtrl-sci2026

Three-dimensional visualization of threading dislocation in GaN by polarized-light microscopy

Yukari Ishikawa, Kisara Matsumoto, Kazuki Ohnishi +1

We demonstrate high-throughput three-dimensional imaging of threading dislocations in ammonothermal GaN wafers using polarized-light microscopy with collimated LED illumination. Th…

cond-mat.mtrl-sci2026

Dislocations in (011)-oriented vertical Bridgman $β$ -Ga $_{2}$ O $_{3}$ substrates

Yongzhao Yao, Daiki Katsube, Hirotaka Yamaguchi +1

Dislocation in (011)-oriented $β$ -Ga $_{2}$ O $_{3}$ substrates grown by the vertical Bridgman method was investigated using X-ray topography (XRT), combined with X-ray reticulography. Tr…

cond-mat.mtrl-sci2026

Determination of Burgers vectors of dislocations in monoclinic $β$ -Ga $_{2}$ O $_{3}$ crystals by large-angle convergent-beam electron diffraction

Yoshihiro Sugawara, Yongzhao Yao, Yukari Ishikawa

We demonstrate the applicability of large-angle convergent-beam electron diffraction (LACBED) for Burgers vector determination in monoclinic $β$ -Ga $_{2}$ O $_{3}$ . The inner product $g \…

cond-mat.mtrl-sci2026

Three-dimensional visualization of lattice defects in $β$ -Ga $_{2}$ O $_{3}$ via synchrotron-radiation Borrmann-effect X-ray topo-tomography

Yongzhao Yao, Daiki Katsube, Hirotaka Yamaguchi +4

beta-Ga2O3 is a promising material for next-generation power electronics; however, its performance is strongly affected by lattice defects such as dislocations. In this study, we d…

cond-mat.mtrl-sci2026

Synchrotron-radiation X-ray topography and reticulography of bulk $β$ -Ga $_{2}$ O $_{3}$ crystals grown by the cold crucible method

Yongzhao Yao, Koki Mizuno, Kazuki Ohnishi +9

The structural properties of a $β$ -Ga $_{2}$ O $_{3}$ single crystal grown by the oxide crystal growth from cold crucible (OCCC) method were investigated using synchrotron radiation X-ray…

cond-mat.mtrl-sci2025

High-throughput, Non-Destructive, Three-Dimensional Imaging of GaN Threading Dislocations with in-Plane Burgers Vector Component via Phase-Contrast Microscopy

Yukari Ishiakwa, Ryo Hattori, Yongzhao Yao +2

We demonstrate a nondestructive, high-throughput method for observing dislocations in GaN (0001) using phase-contrast microscopy (PCM). The PCM images (359x300 $μ$ m $^{2}$ ) analyzed i…

cond-mat.mtrl-sci2025

High-speed, High-Resolution, Three-Dimensional Imaging of Threading Dislocations in beta- $G a_{2} O_{3}$ via Phase-Contrast Microscopy

Yukari Ishiakwa, Daiki Katsube, Yongzhao Yao +2

This study presents a nondestructive, high-resolution method for three-dimensional imaging of threading dislocations in beta- $G a_{2} O_{3}$ (010) using phase-contrast microscopy (PC…

cond-mat.mtrl-sci2025

Kinematical and dynamical contrast of dislocations in thick GaN substrates observed by synchrotron-radiation X-ray topography under six-beam diffraction conditions

Yongzhao Yao, Yoshiyuki Tsusaka, Yukari Ishikawa

Dislocations in a thick ammonothermal GaN substrate were investigated using synchrotron-radiation X-ray topography (SR-XRT) under six-beam diffraction conditions. The high brillian…

Determination of Burgers-vector directions of threading edge dislocations in GaN by phase-contrast microscopy

Groove-shaped defects in as-grown (001)-oriented β-Ga2​O3​ epilayers prepared by halide vapor phase epitaxy

Three-dimensional visualization of threading dislocation in GaN by polarized-light microscopy

Dislocations in (011)-oriented vertical Bridgman β-Ga2​O3​ substrates

Determination of Burgers vectors of dislocations in monoclinic β-Ga2​O3​ crystals by large-angle convergent-beam electron diffraction

Three-dimensional visualization of lattice defects in β-Ga2​O3​ via synchrotron-radiation Borrmann-effect X-ray topo-tomography

Synchrotron-radiation X-ray topography and reticulography of bulk β-Ga2​O3​ crystals grown by the cold crucible method

High-throughput, Non-Destructive, Three-Dimensional Imaging of GaN Threading Dislocations with in-Plane Burgers Vector Component via Phase-Contrast Microscopy

High-speed, High-Resolution, Three-Dimensional Imaging of Threading Dislocations in beta-Ga2​O3​ via Phase-Contrast Microscopy

Kinematical and dynamical contrast of dislocations in thick GaN substrates observed by synchrotron-radiation X-ray topography under six-beam diffraction conditions

Groove-shaped defects in as-grown (001)-oriented $β$ -Ga $_{2}$ O $_{3}$ epilayers prepared by halide vapor phase epitaxy

Dislocations in (011)-oriented vertical Bridgman $β$ -Ga $_{2}$ O $_{3}$ substrates

Determination of Burgers vectors of dislocations in monoclinic $β$ -Ga $_{2}$ O $_{3}$ crystals by large-angle convergent-beam electron diffraction

Three-dimensional visualization of lattice defects in $β$ -Ga $_{2}$ O $_{3}$ via synchrotron-radiation Borrmann-effect X-ray topo-tomography

Synchrotron-radiation X-ray topography and reticulography of bulk $β$ -Ga $_{2}$ O $_{3}$ crystals grown by the cold crucible method

High-speed, High-Resolution, Three-Dimensional Imaging of Threading Dislocations in beta- $G a_{2} O_{3}$ via Phase-Contrast Microscopy