Motoaki Iwaya
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View article: 312 nm UVB Phototherapy Limits Atherosclerosis by Regulating Immunoinflammatory Responses in Mice.
312 nm UVB Phototherapy Limits Atherosclerosis by Regulating Immunoinflammatory Responses in Mice. Open
We demonstrated that 312 nm UVB irradiation limits atherosclerosis by favorably modulating the T cell balance and lipid mediator profile. Our findings indicate that 312 nm UVB phototherapy could be an attractive immunomodulatory approach f…
View article: Hybridly Packaged White Light Emitting Diode Composed of Fluorescent SiC and Nitride‐Based Near‐Ultraviolet Light Emitting Diode
Hybridly Packaged White Light Emitting Diode Composed of Fluorescent SiC and Nitride‐Based Near‐Ultraviolet Light Emitting Diode Open
A combination of fluorescent SiC (f‐SiC) and porous f‐SiC is a promising phosphor material for pure white light emission. Herein, the anodic oxidation condition is optimized to produce porous f‐SiC. Furthermore, a hybridly packaged white l…
View article: Performance Enhancement of Multiple Quantum Shell Nanowire‐Based Micro‐Light Emitting Diodes with Underlying GaInN/GaN Superlattices
Performance Enhancement of Multiple Quantum Shell Nanowire‐Based Micro‐Light Emitting Diodes with Underlying GaInN/GaN Superlattices Open
GaInN/GaN multiple quantum shell (MQS) nanowires (NWs) are of great interest as high‐efficiency micro‐light emitting diodes (micro‐LEDs), mainly due to their quantum confined Stark effect suppression and dry etching insensitivity features.…
View article: Hole Generation in Polarization‐Doped Al<sub><i>x</i></sub>Ga<sub>1–<i>x</i></sub>N (<i>x </i>= 0.9–0.35)‐Graded Layer with Heavily Mg‐Doped Al<sub>0.35</sub>Ga<sub>0.65</sub>N Contact Layer for 275 nm Deep‐Ultraviolet Light‐Emitting Diode
Hole Generation in Polarization‐Doped Al<sub><i>x</i></sub>Ga<sub>1–<i>x</i></sub>N (<i>x </i>= 0.9–0.35)‐Graded Layer with Heavily Mg‐Doped Al<sub>0.35</sub>Ga<sub>0.65</sub>N Contact Layer for 275 nm Deep‐Ultraviolet Light‐Emitting Diode Open
Herein, hole generation in a 60 nm thick polarization‐doped Al x Ga 1– x N ( x = 0.9–0.35)‐graded layer with some Mg doping (5 × 10 18 cm −3 ) is demonstrated by using a 10 nm thick heavily (1 × 10 20 cm −3 ) Mg‐doped Al 0.35 Ga 0.65 N con…
View article: Homoepitaxial Regrowth of AlGaN on AlGaN Templates Prepared via Chemical Mechanical Polishing and Its Application to UV‐B Laser Diodes
Homoepitaxial Regrowth of AlGaN on AlGaN Templates Prepared via Chemical Mechanical Polishing and Its Application to UV‐B Laser Diodes Open
In this article, the homoepitaxial regrowth of AlGaN on AlGaN templates fabricated via chemical mechanical polishing (CMP) on periodically aligned AlN nanopillars is reported on. These templates are lattice relaxed according to X‐Ray diffr…
View article: Effect of Wet Etching on AlGaN‐Based Ultraviolet‐B Laser Diodes Grown on Wet‐Etched Periodic AlN Nanopillars
Effect of Wet Etching on AlGaN‐Based Ultraviolet‐B Laser Diodes Grown on Wet‐Etched Periodic AlN Nanopillars Open
The effect of wet etching on the characteristics of ultraviolet‐B (UV‐B) lasers fabricated on AlGaN templates grown as crystals or wet‐etched AlN nanopillars is compared in detail. Specifically, a tetramethylammonium hydroxide (TMAH) solut…
View article: Over 20% wall plug efficiency of on-wafer GaN-based vertical-cavity surface-emitting laser
Over 20% wall plug efficiency of on-wafer GaN-based vertical-cavity surface-emitting laser Open
We demonstrated an over 20% wall plug efficiency of an on-wafer GaN-based vertical-cavity surface-emitting laser (VCSEL) with a 5 μm aperture. The cavity length of the VCSEL was 4λ optical length, containing a 3.7λ part of GaN-based layers…
View article: Characteristics of Stacked GaInN‐Based Red, Green, and Blue Full‐Color Monolithic μLED Arrays Connected via Tunnel Junctions
Characteristics of Stacked GaInN‐Based Red, Green, and Blue Full‐Color Monolithic μLED Arrays Connected via Tunnel Junctions Open
The use of μLEDs in self‐luminous displays is crucial for the development of high‐efficiency displays for virtual space services. For this purpose, a stacked monolithic GaInN‐based micro light‐eimtting diodes (μLED) device that emits red, …
View article: Analysis of Altered Layers Formed during Substrate Exfoliation of AlGaN Crystals Grown on Periodic AlN Nanopillars Using the Heated‐Pressurized Water Method
Analysis of Altered Layers Formed during Substrate Exfoliation of AlGaN Crystals Grown on Periodic AlN Nanopillars Using the Heated‐Pressurized Water Method Open
This study examines the altered layers formed during the exfoliation of AlN and AlGaN using heated‐pressurized water. Utilizing X‐ray photoelectron spectroscopy (XPS) and X‐ray diffraction (XRD), the study reveals the formation of an alter…
View article: Enhancing the optical properties of organic fluorine compound-encapsulated AlGaN-based ultraviolet light-emitting diodes with Ni/Au reflective electrodes
Enhancing the optical properties of organic fluorine compound-encapsulated AlGaN-based ultraviolet light-emitting diodes with Ni/Au reflective electrodes Open
The development of AlGaN-based high-efficiency UVC-LEDs capable of effectively eliminating viruses and bacteria is desired. In this study, we demonstrate a significant improvement in optical output power (LOP) by applying optical interfere…
View article: Novel UV‐B Phototherapy With a Light‐Emitting Diode Device Prevents Atherosclerosis by Augmenting Regulatory T‐Cell Responses in Mice
Novel UV‐B Phototherapy With a Light‐Emitting Diode Device Prevents Atherosclerosis by Augmenting Regulatory T‐Cell Responses in Mice Open
Background Ultraviolet B (UV‐B) irradiation is an effective treatment for human cutaneous disorders and was shown to reduce experimental atherosclerosis by attenuating immunoinflammatory responses. The aim of this study was to clarify the …
View article: Investigation of emission plane control in GaInN/GaN multiple-quantum shells for efficient nanowire-based LEDs
Investigation of emission plane control in GaInN/GaN multiple-quantum shells for efficient nanowire-based LEDs Open
To improve the emission properties of multiple-quantum-shells nanowire-based LEDs, we assessed the effect of GaInN/GaN superlattices grown at varying growth temperatures, as well as the control of emission plane via p-GaN shell and emissio…
View article: Fabrication of vertical AlGaN-based ultraviolet-B laser diodes using a laser lift-off method
Fabrication of vertical AlGaN-based ultraviolet-B laser diodes using a laser lift-off method Open
Vertical AlGaN-based UV-B laser diodes were fabricated by a laser lift-off method to exfoliate sapphire substrates. These devices were processed on 1 cm 2 square wafers with a polycrystalline sintered AlN substrate as a structural support …
View article: Exfoliation mechanism of AlGaN-based thin films using heated-pressurized water
Exfoliation mechanism of AlGaN-based thin films using heated-pressurized water Open
This study investigated the crystallographic plane dependence of the reaction of AlN and AlGaN using heated-pressurized water under saturated vapor pressure. The results show that the reaction strongly depends on the crystallographic orien…
View article: Stray light reduction in monolithic GaInN-based <i>μ</i>LED arrays for high-definition display realization
Stray light reduction in monolithic GaInN-based <i>μ</i>LED arrays for high-definition display realization Open
Monolithic GaInN-based micro μ LEDs arrays are expected to be applied to ultra-high-definition displays. In this study, stray light behavior of them fabricated on sapphire substrates was investigated. Results reveal that strong stray light…
View article: N-type conducting AlInN/GaN distributed Bragg reflectors with AlGaN graded layers
N-type conducting AlInN/GaN distributed Bragg reflectors with AlGaN graded layers Open
We obtained a 40-pair Si-doped n-type conducting AlInN/GaN distributed Bragg reflector (DBR) with a low surface pit density, 3.0 × 10 6 cm −2 , by introducing 5 nm Si-doped Al 0.39 Ga 0.61 N graded layers grown at high temperature, 1150 °C…
View article: RGB monolithic GaInN-based μLED arrays connected via tunnel junctions
RGB monolithic GaInN-based μLED arrays connected via tunnel junctions Open
We report a 330 ppi monolithic RGB micro light-emitting diodes ( μ LED) array of blue, green and red GaInN-based LEDs stacked on the same wafer. Considering it is challenging to form ohmic electrodes on the plasma-etched p-type GaN surface…
View article: Dimension dependence of current injection path in GaInN/GaN multi-quantum-shell (MQS) nanowire-based light-emitting diode arrays
Dimension dependence of current injection path in GaInN/GaN multi-quantum-shell (MQS) nanowire-based light-emitting diode arrays Open
To light emitting diodes (LEDs), solving the common non-uniform current injection and efficiency degradation issues in (0001) plane micro-LED is essential. Herein, we investigated the light emission characteristics of various mesa sizes an…
View article: In situ cavity length control of GaN-based vertical-cavity surface-emitting lasers with in situ reflectivity spectra measurements
In situ cavity length control of GaN-based vertical-cavity surface-emitting lasers with in situ reflectivity spectra measurements Open
We developed an in situ cavity length control of GaN-based vertical-cavity surface-emitting lasers (VCSELs) with an in situ reflectivity spectra measurement. Firstly, a temperature dependence of a center wavelength of a 40-pair AlInN/GaN D…
View article: Suppression of (0001) plane emission in GaInN/GaN multi-quantum nanowires for efficient micro-LEDs
Suppression of (0001) plane emission in GaInN/GaN multi-quantum nanowires for efficient micro-LEDs Open
GaInN/GaN multi-quantum-shell (MQS) nanowires (NWs) are gaining increasing attention as promising materials for developing highly efficient long-wavelength micro-light emitting diodes (LEDs). To improve the emission properties in GaInN/GaN…
View article: Emission characteristics of GaInN/GaN multiple quantum shell nanowire-based LEDs with different <i>p</i>-GaN growth conditions
Emission characteristics of GaInN/GaN multiple quantum shell nanowire-based LEDs with different <i>p</i>-GaN growth conditions Open
Improving current injection into r - and m -planes of nanowires (NWs) is essential to realizing efficient GaInN/GaN multiple quantum shell (MQS) NW-based light-emitting diodes (LEDs). Here, we present the effects of different p -GaN shell …
View article: Three-Method Hybrid Numerical Simulation for Surface-Plasmon-Enhanced GaInN-Based Light-Emitting Diodes with Metal-Embedded Nanostructures
Three-Method Hybrid Numerical Simulation for Surface-Plasmon-Enhanced GaInN-Based Light-Emitting Diodes with Metal-Embedded Nanostructures Open
In this paper, a hybrid numerical simulation tool is introduced and performed for GaInN-based light-emitting diodes (LEDs) with metal-embedded nanostructure to theoretically predict external quantum efficiency (EQE), which composed of fini…
View article: Voltage-Controlled Anodic Oxidation of Porous Fluorescent SiC for Effective Surface Passivation
Voltage-Controlled Anodic Oxidation of Porous Fluorescent SiC for Effective Surface Passivation Open
This study investigated the fabrication of porous fluorescent SiC using a constant voltage-controlled anodic oxidation process. The application of a high, constant voltage resulted in a spatial distinction between the porous structures for…
View article: Identifying the cause of thermal droop in GaInN-based LEDs by carrier- and thermo-dynamics analysis
Identifying the cause of thermal droop in GaInN-based LEDs by carrier- and thermo-dynamics analysis Open
This study aims to elucidate the carrier dynamics behind thermal droop in GaInN-based blue light-emitting diodes (LEDs) by separating multiple physical factors. To this end, first, we study the differential carrier lifetimes (DCLs) by meas…
View article: Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD
Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD Open
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 nan…
View article: Structural and optical impacts of AlGaN undershells on coaxial GaInN/GaN multiple-quantum-shells nanowires
Structural and optical impacts of AlGaN undershells on coaxial GaInN/GaN multiple-quantum-shells nanowires Open
The superior crystalline quality of coaxial GaInN/GaN multiple-quantum shell (MQS) nanowires (NWs) was demonstrated by employing an AlGaN undershell during metal-organic chemical vapor deposition. Scanning transmission electron microscopy …
View article: Growth and Characterization of Core-Shell Structures Consisting of GaN Nanowire Core and GaInN/GaN Multi-Quantum Shell
Growth and Characterization of Core-Shell Structures Consisting of GaN Nanowire Core and GaInN/GaN Multi-Quantum Shell Open
The growth of dislocation-free and uniform GaN nanowires and high emission efficiency in a GaInN/GaN multi-quantum shell (MQS) are demonstrated. Simultaneous-supply-mode metal-organic vapor phase epitaxy and a high growth temperature are a…