A5079522121- Semiconductor Quantum Structures and Devices
- GaN-based semiconductor devices and materials
- Radio Frequency Integrated Circuit Design
- Balance, Gait, and Falls Prevention
- Metal and Thin Film Mechanics
- Mechanical Engineering and Vibrations Research
- Metal Alloys Wear and Properties
- Cerebral Palsy and Movement Disorders
- ZnO doping and properties
- Advanced Power Amplifier Design
- Engineering Structural Analysis Methods
- Vacuum and Plasma Arcs
- Mechanical Failure Analysis and Simulation
- Metallurgy and Material Forming
- Children's Physical and Motor Development
- Nutrition and Health in Aging
- Physics of Superconductivity and Magnetism
- Semiconductor materials and devices
- Semiconductor Lasers and Optical Devices
- Diamond and Carbon-based Materials Research
- Lower Extremity Biomechanics and Pathologies
- Mechanical stress and fatigue analysis
- Advanced machining processes and optimization
- Engineering Applied Research
- Welding Techniques and Residual Stresses
Shibaura Institute of Technology
2015-2025
The University of Tokyo
2023
Reitaku University
2023
Nishikyushu University
2015-2022
Novartis (Japan)
2022
Kanzaki (Japan)
2022
Kokura Memorial Hospital
2006-2021
University of California, Santa Barbara
2011-2013
Shimonoseki City University
2010
Sakai Chemical Industry (Japan)
2008
We report a high-power blue light-emitting diode (LED) with high external quantum efficiency and low droop on free-standing (20) GaN substrate. At forward current of 20 mA, the LED showed peak 52% an output power 30.6 mW. In higher density regions, also outstanding performance, ratios 0.7% at 35 A/cm2, 4.3% 50 8.5% 100 14.3% 200 A/cm2. The A/cm2 were 266.5 mW 45.3%, respectively.
We report indium incorporation properties on various nonpolar and semipolar free-standing GaN substrates. Electroluminescence characterization x-ray diffraction (XRD) analysis indicate that the (202¯1¯) (112¯2) planes have highest rate among studied planes. also show both composition polarization-related electric fields impact emission wavelength of quantum wells (QWs). The different magnitudes directions for each orientation result in potential profiles QWs, leading to wavelengths at a...
We demonstrate a small-area (0.1 mm2) semipolar (2021) blue (447 nm) light-emitting diode (LED) with high light output power (LOP) and external quantum efficiency (EQE) by utilizing single 12-nm-thick InGaN well. The LED had pulsed LOPs of 140, 253, 361, 460 mW, EQEs 50.1, 45.3, 43.0, 41.2%, at current densities 100, 200, 300, 400 A/cm2, respectively. device showed little shift narrow full width half maximum (FWHM). Micro-electroluminescence (µ-EL) scanning transmission electron microscope...
The optical polarization ratio of spontaneous emission was investigated by electroluminescence measurements for semipolar (202¯1¯) InGaN/GaN light-emitting diodes, covering the blue to green spectral range. Devices fabricated on substrates exhibit ratios ranging from 0.46 at 418 nm 0.67 519 nm. These are significantly higher than those reported (202¯1) devices. valence band energy separation is extracted and consistent with increased theoretical predictions. Quantum well interdiffusion...
We study the optical spectral properties for green semipolar (20) and (201) light-emitting diode (LED) with same indium compositions. Compared to devices, fabricated micro-LED (∼0.005 mm2) showed negligible blue shift smaller full width at half maximum (FWHM) up extremely high current densities (10,000 A/cm2). Theoretical simulation indicates that InGaN quantum well (QW) has reduced polarization-related effects due combined of electric field cancelling Coulomb screening effect. In addition,...
We investigate the influence of polarity on carrier transport in single-quantum-well and multiple-quantum-well (MQW) light-emitting diodes (LEDs) grown semipolar (202¯1) (2021¯) orientations free-standing GaN. For MQW LEDs with opposite to conventional Ga-polar c-plane LEDs, polarization-related electric field QWs results an additional energy barrier for carriers escape QWs. show that same have a more uniform distribution lower forward voltage than LEDs.
Abstract Using a novel hybrid conductor with intercalated multilayer graphene (I-MLG) and Ni, it was demonstrated that the area of radio frequency (RF) patch antenna at around 18 GHz can be reduced by one-third. Improved intercalation doping MLG realized split-CVD method for improved crystallinity uniformity higher to MLG. With process improvement, sheet resistance I-MLG layer current considered flow preferentially in skin effect high frequencies, kinetic inductance induced layer. In...
Abstract The 2024 Noto-Hanto earthquake with a magnitude of 7.6 occurred in the Noto Peninsula on January 1, 2024. mainshock had reverse fault focal solution and direction compression axis was northwest–southeast. In Peninsula, swarms have been observed since December 2020. contrast to this swarm activity, extending marine area. Therefore, we performed rapid response seafloor seismic observation source region its vicinity. We deployed 34 free-fall pop-up type ocean bottom seismometers (OBSs)...
Ferroelectric properties of a Pb(Zi, Ti)O 3 (PZT) capacitor with thin SrRuO (SRO) films within both electrodes were investigated in detail. Thin SRO 10 nm thickness markedly improve the electrical performance, such as switching charge (Qsw), saturation characteristics hysteresis curve and imprint performance even at an elevated temperature. It should also be noted that there was no Qsw degradation after 5×10 read/write cycles 5 V. No leakage current increase test observed. The results...
We report on the thermal performance of electroluminescence 12-nm-thick single-quantum-well (SQW) InGaN blue light-emitting diodes (LEDs) grown semipolar (2021) plane. At a current density 100 A/cm2, external quantum efficiency (EQE) decreased by 9.7% when temperature was increased from 20 to °C. Hot/cold factors were more than 0.9 at densities greater A/cm2. A high characteristic 900 K and low junction 68 °C also measured using bare LED chips.
We report on void defect formation in (202¯1¯) semipolar InGaN quantum wells (QWs) emitting the green spectral region. Fluorescence and transmission electron microscopy studies indicate that this type of is associated with voids {101¯1}, {101¯0}, {0001¯} side facets QW Systematic growth show can be effectively suppressed by reducing rate for active Green light-emitting diodes (LEDs) reduced region showed enhanced power wavelength performance. The improved LED performance attributed to absence defects
The droop property of blue GaN light emitting diodes (LEDs) has been improved by creating a 9 quantum well (QW) LED on patterned sapphire substrate (PSS). ratio was from 45.9 to 7.6%. At wavelength 447 nm, and with standard on-header packaging, the 9QW PSS-LED had an output power 27.6 mW EQE 49.7% at current 20 mA. remains linear increasing drive current, even up relatively high density, is almost constant.
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Ravi Shivaraman, Y. Kawaguchi, S. Tanaka, P. DenBaars, Nakamura, J. Speck; Comparative analysis of 202¯1 202¯1¯ semipolar GaN light emitting diodes using atom probe tomography. Appl. Phys. Lett. 24 June 2013; 102 (25): 251104. https://doi.org/10.1063/1.4812363 Download citation file: Ris (Zotero) Reference...
Stable d.c. electroluminescence is observed in a cell with M-I-S structures the form of thin films (Ta–Ta2O5–ZnS: TbF3–Au). To be able to observe cell, Ta2O5 insulating layer must about 1000 Å–5000 Å thick and treated by heating air at 250°C for 10 minutes. Through such heat treatment, conductance increases remarkably (about 103 times). The increase due transition from an anomalous Poole-Frenkel effect normal one conduction process. This heat-treated plays important role creation hot...
Introduction The prevalence of knee osteoarthritis is much higher in Caucasians than Asians or black people. Few population-based studies regarding the incidence were found, with being Japanese Caucasians. However, strict comparisons among these are limited, because definition not same for each study. A few risk factors osteoarthrit established, such as female gender and obesity. Several crosssectional have found that presence a previous injuryis significantly associated osteoarthritis, but...
Abstract We elucidated that hexaalkoxytriphenylenes (HATs) are useful as a hole transport layer (HTL) in organic light emitting diodes (OLEDs). In particular, the insertion of thin phthalocyanine between anode and HTL drastically improved electroluminescent (EL) performance. Furthermore, we observed alkyl chain length HATs greatly affected carrier EL properties.
本研究は，筆者らが開発した足把持力測定器とその測定器から得られる計測データについて紹介した。本測定器は，ひずみゲージを用いることによって，最小0.1 kgからの足把持力と足把持力の最大値到達時間が計測できる。計測データの紹介は，健常成人男性16名（平均年齢22.3±5.5歳）の左右32肢を対象に行った。対象者の足把持力は平均17.4±4.5 kgであり，最大値到達時間は0.66±0.26秒であった。また，測定値の再現性は，足把持力がICC = 0.953，最大値到達時間がICC 0.723であり，臨床場面での使用に十分に耐え得る再現性を有することが示唆された。