A5102835919- GaN-based semiconductor devices and materials
- ZnO doping and properties
- Ga2O3 and related materials
- Metal and Thin Film Mechanics
- Photocathodes and Microchannel Plates
- Semiconductor Quantum Structures and Devices
- Gas Sensing Nanomaterials and Sensors
- Advanced Photocatalysis Techniques
- Copper-based nanomaterials and applications
- Plasma Diagnostics and Applications
- Acoustic Wave Resonator Technologies
- Catalysis and Hydrodesulfurization Studies
- Advanced Battery Technologies Research
- Transition Metal Oxide Nanomaterials
- Semiconductor materials and devices
- Semiconductor Lasers and Optical Devices
- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Ferroelectric and Negative Capacitance Devices
- Industrial Gas Emission Control
- Organic Light-Emitting Diodes Research
- Advanced Memory and Neural Computing
- Magnetic properties of thin films
- Electronic and Structural Properties of Oxides
Karlsruhe Institute of Technology
2025
King Abdullah University of Science and Technology
2019-2024
Chiba University
2023
Kootenay Association for Science & Technology
2020-2021
This work investigates the influence of residual stress on performance InGaN-based red light-emitting diodes (LEDs) by changing thickness underlying n-GaN layers. The in-plane in LED structure depends layer. Decreased resulting from increased layers improves crystalline quality InGaN active region allowing for a higher growth temperature. electroluminescence intensity LEDs is factor 1.3 when layer 2 to 8 μm. Using 8-μm-thick layers, 633-nm-wavelength are realized with light-output power 0.64...
Abstract Here we report InGaN-based red light-emitting diodes (LEDs) grown on ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mn>2</mml:mn> <mml:mo stretchy="true">¯</mml:mo> </mml:mover> <mml:mn>01</mml:mn> </mml:math> ) β -Ga 2 O 3 substrates. AlN/AlGaN strain-compensating layers and hybrid multiple-quantum-well structures were employed to improve the crystalline-quality of InGaN active region. A bare LED showed that peak wavelength, light...
Here, we report highly efficient InGaN-based red light-emitting diodes (LEDs) grown on conventional c-plane-patterned sapphire substrates. An InGaN single quantum well active layer provides the spectral emission. The 621-nm-wavelength LEDs exhibited high-purity emission with a narrow full-width at half-maximum of 51 nm. packaged LED’s external efficiency, light-output power, and forward voltage 621 nm peak wavelength 20 mA (10.1 A/cm2) injection current were 4.3%, 1.7 mW, 2.96 V,...
We demonstrated amber InGaN <inline-formula> <tex-math notation="LaTeX">$47\times 47\,\,\mu \text{m}^{{2}}$ </tex-math></inline-formula> micro-light-emitting diodes (<inline-formula> notation="LaTeX">$\mu $ </tex-math></inline-formula>LEDs) with the peak wavelength of 606 nm and full-width at maximum (FWHM) 50 20 A/cm<sup>2</sup>. The </tex-math></inline-formula>LEDs exhibited a 33-nm blue-shift obtain broader FWHMs to approximately 56 5 100 on-wafer external quantum efficiency was...
We demonstrated <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mn>10</mml:mn> <mml:mo>×</mml:mo> </mml:mrow> </mml:math> arrays of InGaN id="m2"> <mml:mn>17</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>μm</mml:mi> micro-light-emitting diodes (μLEDs) with a peak wavelength from 662 to 630 nm at id="m3"> <mml:mi>–</mml:mi> <mml:mn>50</mml:mn> <mml:mi mathvariant="normal">A</mml:mi> <mml:mo>/</mml:mo> <mml:msup> <mml:mi>cm</mml:mi>...
Fabrication of indium tin oxide (ITO) was optimized for InGaN-based amber/red light-emitting diodes (LEDs). A radiofrequency sputtering reduced the sheet resistivity ITO at low pressures, and a subsequent two-step annealing resulted in (below 2×10-4 Ωcm) high transmittance (over 98%) amber red regions between 590 nm to 780 nm. Double layers by could form an excellent ohmic contact with p-GaN. Application double on LEDs enhanced light output power 15.6% 13.0%, respectively, compared those...
Improving interfacial stability between cathode active material (CAM) and solid electrolyte (SE) is vital for developing high-performance all-solid-state batteries (ASSBs), with compatibility issues among the cell components representing a major challenge. CAM surface coating chemically inert ion conductor promising approach to suppress side reactions occurring at interfaces. Another strategy mitigate mechanical degradation involves utilizing single-crystalline particle morphologies. Their...
Abstract We report the characterization of a N-polar InGaN layer deposited by metalorganic vapor-phase epitaxy on ScAlMgO 4 (0001) (SAM) substrate without low-temperature buffer layer. The was tensile-strained, and its stoichiometry corresponded to In 0.13 Ga 0.87 N. also present microstructural observation InGaN/SAM interface via integrated differential phase contrast-scanning transmission electron microscopy. results show that between SAM occurs O atoms O–Sc surface (Ga,In) InGaN.
Tungsten trioxide (WO3) is an intrinsic n-type semiconductor that can be prepared to exhibit a piezoresponse through doping and heat treatment strategies. We report the in platinum-doped WO3 thin films, by RF/DC cosputtering, followed postdeposition annealing at 600 °C. Measurements using Switching Spectroscopy Piezo Force Microscopy (SS-PFM) reveal domains with different polarization orientations hysteresis behavior, corresponding piezoelectric coefficient of d 33 = 97 ± 6 pmV-1. Low-angle...
We have improved the InGaN/GaN heterointerface to achieve higher energy conversion efficiency by replacing a uniform InGaN layer with graded In-content layer. Even In0.08Ga0.92N/GaN heterostructure has large conduction band offset, which is enough suppress photocurrent in photocatalytic system. The structures were grown metalorganic vapor-phase epitaxy changing TMIn flow rate gradually. X-ray reciprocal space mapping confirmed structures. structure significantly increased and H2 generation...
Here, we proposed fabricating ultra-small InGaN-based micro-light-emitting diodes (µLEDs). The selective p-GaN areas were intentionally passivated using a H2 plasma treatment and served as the electrical isolation regions to prevent current from injecting into InGaN quantum wells below. Three kinds of green µLEDs, two squircle shapes with widths 5 4 µm one circular shape diameter 2.7 µm, successfully realized. current-voltage characteristics indicate that series resistance turn-on voltage...
We herein report the growth of phosphor-free InGaN-based white light-emitting diodes (LEDs) by metalorganic vapor-phase epitaxy. The active region consists blue and red InGaN quantum wells (QWs). To improve current injection generate broadband emission, V-pit structures in LEDs were fabricated intentionally before growing QWs. monolithic emit range 410–770 nm and, tuning current, can cover correlated color temperature (CCT) values corresponding to warm white, natural cool white....
We fabricated indium gallium nitride (InGaN) red light-emitting diodes (LEDs) with a peak emission wavelength of 649 nm and investigated their electroluminescence (EL) properties. An additional separated in the EL spectrum LEDs at 20 mA was observed 465 nm. This also exhibits blue-shift increasing currents as does main peak. Using high-resolution microscopy, we many point-like spots images below 1 mA. However, these cannot be identified above 5 because from quantum wells (QWs) is much...
Hydrogen is considered one of the most promising decarbonized fuels. However, its applicability limited due to ecological constraints production. sulfide (H 2 S) widely available in oil and gas reservoirs has potential becoming an energetically favorable source hydrogen. Nevertheless, electrochemical separation into H elemental sulfur not been successfully achieved at industrial scale, poisoning electrodes oxidation half-reaction. This review highlights progress direct electrolytic S below...
We have grown high-crystallinity InGaN layers on ScAlMgO4 (SAM) substrates using metalorganic vapor-phase epitaxy. prepared atomically flat SAM by cleaving them along the c-plane and utilized direct growth without any low-temperature buffer layer. The resulting layer has a distinct hexagonal hillock morphology remarkable crystalline quality. x-ray rocking curve measurements showed that (0002̄) (10–1–2) peaks full widths at half-maximum are as good 384 481 arcsec, respectively. calculated...
Abstract Nitrides are of particular interest in energy applications given their suitability to photocatalytically generate H 2 from aqueous solutions. However, one the drawbacks nitrides is decomposition they suffer when used photoelectrochemical cells. Here, we report improvement catalytic performance and chemical stability a GaN electrode it decorated with Fe O 3 particles compared an undecorated electrode. Our results show higher reaction rate /GaN electrode, that photocorrosion marks...
Fabrication of indium tin oxide (ITO) was optimized for InGaN-based amber/red light-emitting diodes (LEDs). A radiofrequency sputtering reduced the sheet resistivity ITO at low pressures, and a subsequent two-step annealing resulted in (below 2×10-4 Ωcm) high transmittance (over 98%) amber red regions between 590 nm to 780 nm. Double layers by could form an excellent ohmic contact with p-GaN. Application double on LEDs enhanced light output power 15.6% 13.0%, respectively, compared those...
We can grow high-In-content InGaN-based red LED structures by our original MOVPE. Using commercial blue and green wafers, we have fabricated RGB micro-LEDs monochromatic 10 X micro-LED arrays. The size of the was 17 m square. array showed peak wavelength at 630 nm FWHM 62.9 50 A/cm2. Its light output power density as high 176 mW/cm2, absolute EQE approximately 0.4%. arrays covered good 81.3% Rec. 2020 color space in CIE 1931
We report the fabrication of a GaN-based photoelectrode with CoOx as cocatalyst for photoelectrochemical H2 generation from water. confirmed that prevented GaN photocorrosion partially during water photoelectrolysis reaction and it has superior performance when is deposited particles instead thin film. demonstrated CoOx/GaN capable generating at quasi-stable rate least 20 h. Scanning transmission electron microscopy analyses agglomerate in sparse polycrystalline clusters, which were formed...
For the development of efficient red LEDs with high-In-content InGaN quantum wells (QWs), we have developed micro-flow-channel MOVPE method. This can grow at higher growth temperatures, resulting in quality. Also, introduced strain compensation method QW region. Barrier layers consisting Al(Ga)N could compensate for a compressive induced by InGaN. The has improved LED efficiency and elongated peak EL electroluminescence.
GaN and NiO/GaN electrodes were characterized by impedance spectroscopy measurements in 0.1 M NaOH. We observed the suppression of surface states capacitance due to modification chemical state superficial Ga atoms NiO. This result suggests that carriers involved photocorrosion alkaline conditions originate its states. In addition, we epitaxial relationship between NiO particles deposited on transmission electron microscopy, finding NiO{111}||GaN{0002} NiO[220] ||GaN[112¯0] symmetry constraints.
We investigated the performance of InGaN-based red and green micro LEDs ranging from 98 × μm<sup>2</sup> to 17 μm<sup>2</sup>. The 47 micro-LEDs were obtained an on-wafer EQE 0.36% at peak wavelength 626 nm 4 A/cm<sup>2</sup>. was close primary color defined in Rec. 2020 standard CIE 1931. also evaluated temperature stability micro-LEDs. characteristic 50 411 K under 10 A/cm<sup>2</sup> operation for LEDs, respectively.