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Article
TM- and TE-polarization-selective narrowband perfect absorber for near-ultraviolet light using Fano resonance in an aluminum nanohole array structure
A wavelength- and polarization-selective absorber for near-ultraviolet light with a wavelength of 375 nm was theoretically designed and experimentally verified. Furthermore, the absorption mechanism was elucid...
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Article
Fabrication and Operation Analysis of a Surface-Plasmon Sensor Using a Nonpropagating Mode
Our research focuses on the development of a surface-plasmon sensor that uses a stationary surface plasmon, referred to as a “nonpropagating mode.” This mode is observed when light is incident perpendicularly ...
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Article
Open AccessFabrication of perfect plasmonic absorbers for blue and near-ultraviolet lights using double-layer wire-grid structures
This study proposes using double-layer wire-grid structures to create narrow-band, perfect plasmonic absorbers, which depend on polarization, for the short-wavelength visible and near-ultraviolet regions of th...
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Article
Facet-control in selective area growth (SAG) of a-plane GaN by MOVPE
Selective area growth (SAG) of a-plane GaN grown on r-plane sapphire with a stripe orientation along <1-100> was investigated. The key technology of facet-control is optimizing the growth temperature and the r...
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Article
Growth of High Quality c-plane AlN on a-plane Sapphire
c-plane (0001) AlN layers were grown on sapphire (11-20) and (0001) substrates by hydride vapor phase epitaxy (HVPE) and metal-organic vapor phase epitaxy (MOVPE), respectively. The growth temperatures were ad...
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Article
Excitation mechanism of surface plasmon polaritons in a double-layer wire grid structure
We characterize the optical properties of a double-layer wire grid structure and investigate in detail the excitation mechanism of surface plasmon polaritons (SPPs). Angular spectra for the transmittance of th...
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Article
Extraordinary Optical Transmission Exhibited by Surface Plasmon Polaritons in a Double-Layer Wire Grid Polarizer
We fabricate a double-layer wire grid polarizer (WGP) and perform optical characterization to clarify the relationship between the structural and polarization characteristics. For normal incidence, the fabrica...
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Article
Fabrication of GaN with Buried Tungsten (W) Structures Using Epitaxial Lateral Overgrowth (ELO) via LP-MOVPE
A buried tungsten (W) mask structure with GaN is successfully obtained by epitaxial lateral overgrowth (ELO) technique via low-pressure metalorganic vapor phase epitaxy (LP-MOVPE). The selectivity of GaN growt...
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Article
Selective Area Growth (SAG) and Epitaxial Lateral Overgrowth (ELO) of GaN Using Tungsten Mask
Selective area growth (SAG) and epitaxial lateral overgrowth (ELO) of GaN using tungsten (W) mask by metalorganic vapor phase epitaxy (MOVPE) and hydride vapor phase epitaxy (HVPE) have been studied. The selec...
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Article
Hydrogen and Nitrogen Ambient Effects on Epitaxial Lateral Overgrowth (ELO) of GaN Via Metalorganic Vapor-Phase Epitaxy (MOVPE)
Ambient gas effect on the epitaxial lateral overgrowth (ELO) of GaN via metalorganic vapor-phase epitaxy (MOVPE) on a MOVPE-grown GaN (0001) / sapphire (0001) substrate with a SiO2 stripe mask has been studied by...
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Article
Fabrication of a binary diffractive lens for controlling the luminous intensity distribution of LED light
To control the luminous intensity of an light-emitting diode (LED), we designed and fabricated a binary diffractive lens by electron beam lithography on a poly(ethylene terephthalate) (PET) film. We showed tha...
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Chapter
Fundamental Properties of Wide Bandgap Semiconductors
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Chapter
Crystal Growth
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Article
Fabrication and characterization of UV Schottky detectors by using a freestanding GaN substrate
GaN ultraviolet (UV) detectors were fabricated on a freestanding GaN substrate with low dislocation density. The resulting dark current density was below 1 nA/cm-2 at -8 V reverse bias, which was about 3 order...
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Article
Reduction of dislocation density in AlGaN with high AlN molar fraction by using a rugged AlN epilayer
A method for making AlGaN with a high AlN molar fraction and low dislocation density is needed for fabricating deep ultraviolet emitters and detectors. In this study, we reduced the dislocation density in AlGa...
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Article
Characterization of III-nitride Based Schottky UV Detectors with Wide Detectable Wavelength Range (360–10 nm) using Synchrotron Radiation
Characterizations of transparent Schottky barrier GaN and AlGaN UV detectors in the vacuum UV (VUV) and soft X-ray (SX) region using synchrotron radiation are described. In the GaN UV detectors, the responsivi...
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Article
New buffer layer technique using underlying epitaxial AlN films for high-quality GaN growth
We demonstrate high-quality epitaxial AlN films on C-plane sapphire as a new buffer layer technique for the growth of high-quality GaN. The obtained GaN films were atomically flat and the full width at half ma...
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Article
Characterization of high-quality epitaxial AlN films grown by MOVPE
This paper presents the correlation between overall crystal mosaicities and dislocation behaviors of high-quality AlN epitaxial films grown on a C-plane sapphire substrate using a low-pressure metal organic va...
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Article
Effects of the Schottky electrode structure in GaN based UV-VUV (50-360 nm) photodetector
Characterization of Schottky barrier UV detectors with a comb-shaped electrode and a transparent electrode for VUV region using synchrotron radiation was carried out. These Schottky type detectors are effectiv...
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Article
Effect of Ge in Cl2 Plasma for Reactive Ion Etching of GaN
We investigated the effect of Ge and Si in Cl2 plasma on reactive ion etching (RIE) of GaN. The etched surfaces of GaN were smooth, and high etch rates of 0.63 μm/min and 0.41 μm/min were obtained using a Ge plat...
