A5100341499- Laser-Plasma Interactions and Diagnostics
- Laser-Matter Interactions and Applications
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Advanced Fiber Optic Sensors
- Laser-induced spectroscopy and plasma
- Electronic and Structural Properties of Oxides
- Photonic Crystal and Fiber Optics
- Laser Material Processing Techniques
- Advanced Photocatalysis Techniques
- Advanced X-ray Imaging Techniques
- Laser Design and Applications
- Iron-based superconductors research
- Physics of Superconductivity and Magnetism
- Copper-based nanomaterials and applications
- Solid State Laser Technologies
- Magnetic and transport properties of perovskites and related materials
- Optical Coherence Tomography Applications
- Atomic and Molecular Physics
- Perovskite Materials and Applications
- 2D Materials and Applications
- Ferroelectric and Piezoelectric Materials
- Terahertz technology and applications
- Ocular and Laser Science Research
- Chalcogenide Semiconductor Thin Films
Gwangju Institute of Science and Technology
2014-2024
University of Illinois Urbana-Champaign
2022-2024
Korea Advanced Institute of Science and Technology
2022
Government of the Republic of Korea
2017-2019
Gwangju University
2019
Kyungpook National University
2015
Handong Global University
2014
Max Planck Institute of Microstructure Physics
2010
Korea Photonics Technology Institute
2002-2009
Shenyang Aluminum & Magnesium Engineering & Research Institute (China)
1993
The electroluminescence intensity of a silicon quantum dot (Si QD) light-emitting diode (LED) with an Ag layer containing particles can be enhanced by 434% relative to Si QD LED without layer. large enhancement is attributed increase in radiative efficiency as result coupling between QDs and localized surface plasmons increased current injection through improved carrier tunneling into QDs.
In photoelectrochemical (PEC) water splitting, BiVO4 is considered the most promising photoanode material among metal oxide semiconductors because of its relatively narrow optical bandgap and suitable band structure for oxidation. Nevertheless, until now, solar-to-hydrogen conversion efficiency has shown significant limitations commercialization poor charge transport. Various strategies, including formation a heterojunction doping electron donors, have been implemented to enhance transport...
Abstract Although organometal halide perovskites (OHPs) have desirable photovoltaic properties, their photoelectrochemical (PEC) water‐splitting application for hydrogen production is limited by the instability originating from intrinsic ionic defects and hygroscopic vulnerability. Herein, a highly efficient stable OHP‐based photocathode achieved new zwitterion (L‐proline) passivation eutectic gallium indium alloy (EGaIn) encapsulation method described. The zwitterion, which has both cations...
To date, the in situ fabrication of large-scale van der Waals multi-heterojunction transition metal dichalcogenides (multi-TMDs) is significantly challenging using conventional deposition methods. In this study, vertically stacked centimeter-scale multi-TMD (MoS2/WS2/WSe2 and MoS2/WSe2) thin films are successfully fabricated via sequential pulsed laser (PLD), which an growth process. The MoS2/WS2/WSe2 film on p-type silicon (p-Si) substrate designed to form multistaggered gaps (type-II band...
Boosting dielectric permittivity representing electrical polarizability of materials has been considered a keystone for achieving scientific breakthroughs as well technological advances in various multifunctional devices. Here, we demonstrate sizable enhancements low-frequency responses oxygen-deficient oxide ceramics through specific treatments under humid environments. Ultrahigh (~5.2 × 10 6 at 1 Hz) is achieved by hydrogenation, when Ni-substituted BaTiO 3 are exposed to high humidity....
Fast protons are observed by a newly developed online time-of-flight spectrometer, which provides shot-to-shot proton-energy distributions immediately after the irradiation of laser pulse having an intensity ∼1018W∕cm2 onto 5-μm-thick copper foil. The maximum proton energy is found to increase when fs prepulse arriving 9ns before main increases from 1014 1015W∕cm2. Interferometric measurement indicates that preformed-plasma expansion at front surface smaller than 15μm, corresponds spatial...
Abstract The high‐power femtosecond laser has now become an excellent scientific tool for the study of not only relativistic laser–matter interactions but also applications. depends on Kerr‐lens modelocking (KLM) and chirped‐pulse amplification (CPA) technique. An all‐Ti:sapphire‐based 30‐fs PW CPA laser, which is called PULSER (Petawatt Ultrashort Laser System Extreme Science Research) been recently constructed being used accelerating charged particles (electrons protons) generating...
The photoelectrochemical properties of template-engineered epitaxial BiVO<sub>4</sub> photoanodes have been enhanced approximately 10 times that bare BiVO<sub>4</sub>.
Reliable CuBi<sub>2</sub>O<sub>4</sub>/NiO heterostructure thin film photocathodes with high density and sharp interface are demonstrated <italic>via</italic> pulsed laser deposition.
We have developed a new type of all-fiber band-rejection filter consisting helicoidal long-period fiber grating pair opposite helicities, which provides highly flexible spectral control over the rejection bandwidth. The detailed fabrication method and operation principles proposed bandwidth-tunable are described. device enables unique bandwidth tuning more than 14 nm at level 15 dB, with low insertion loss polarization-dependent achieved by adjusting torsion stress.
Abstract To develop strategies for efficient photo‐electrochemical water‐splitting, it is important to understand the fundamental properties of oxide photoelectrodes by synthesizing and investigating their single‐crystal thin films. However, challenging synthesize high‐quality films from copper‐based due occurrence significant defects such as copper or oxygen vacancies grains. Here, CuBi 2 O 4 (CBO) film photocathode achieved using a NiO template layer grown on SrTiO 3 (STO) (001) substrate...
Although an annealing approach for bulk or thick Bi–Te material had been done the enhancement of thermoelectric efficiency, this is first time to report process a nanostructure with high aspect ratio. As well-known, Seebeck coefficient, one efficiency factors, strongly influenced by chemical composition material. However, tellurium element tends be easily evaporated in high-temperature range (more than 400 °C) due its low melting point and evaporation pressure. Furthermore, it more serious...
Abstract To date, the fabrication of highly uniform large‐scale monolayer and few‐layer p‐type WSe 2 throughout entire substrate, especially on SiO /Si substrates is significantly challenging one most important issues. Here, thin films a centimeter‐scale substrate via pulsed laser deposition reported. The number layers thickness, controlled by varying pulses, determined transmission electron microscopy analysis. high uniformity as‐grown film verified Raman peak position intensity, estimated...
Nonequilibrium deposition is a remarkable method for the in situ growth of unique nanostructures and phases functionalization thin films. We introduce distinctive structure mixed-phase, composed BiVO4 β-Bi2O3, photoelectrochemical water splitting. The mixed-phase fabricated via nonequilibrium by adjusted oxygen partial pressure. According to density functional theory calculations, we find that vanadium exsolution can be facilitated introducing vacancies, enabling fabrication nanostructured...
Abstract Although nanoscale deformation, such as nanostrain in iron-chalcogenide (FeSe x Te 1− , FST) thin films, has attracted attention owing to its enhancement of general superconducting properties, including critical current density ( J c ) and transition temperature, the development this technique proven be an extremely challenging complex process thus far. Herein, we successfully fabricated epitaxial FST film with uniformly distributed by injection a trace amount CeO 2 inside matrix...
P-type thermoelectric bismuth telluride nanowires were fabricated by pulsed electrodeposition in anodic aluminium oxide (AAO) membranes. Subsequently, the annealed at 423, 523 and 673 K an inert atmosphere for 4 h. With increasing temperature, it was observed that Te compound incongruently sublimates due to its high vapor pressure, leading disproportionation (from Bi2Te3 Bi4Te3via Bi4Te5). The crystalline structure of then investigated using XRD SAED, with nanowire compositions EDX attached...
Achieving high critical current density (Jc) under a magnetic field in Fe based superconductors is indispensable for practical applications. Here we report that over 1 MA cm−2 (13 T) can be achieved BaZrO3 (BZO) incorporated Ba(Fe,Co)2As2 (Co-Ba122) thin film grown on CaF2 substrate using pulsed laser deposition. The magnetization Jc of Co-Ba122 with 2 mol.% BZO reaches 1.3 (Hǁc, 13 T and 4.2 K), 14 times higher than pure film. Transmission electron microscopy observation revealed forms...
To improve the photoelectrochemical performance of photoelectrodes, various modifications such as doping electron donors, morphology control, and adoption catalysts have been widely implemented, among which formation type-II heterojunctions has recognized an effective method to significantly charge transport efficiency photoelectrodes. In this regard, we report on in situ high-quality epitaxial BiVO4/Bi4V2O11 heterojunction thin-film photoanode fabricated by using pulsed laser deposition...
Abstract Antiferromagnetic-paraelectric SrMnO 3 (SMO) has aroused interest because of the theoretical strong coupling between ferroelectric and ferromagnetic states with increasing epitaxial strain. In strained SMO films, <110> polarized state polar distortions have been observed, although high leakage currents air degradation limited their experimental verification. We herein provide a conclusive demonstration room-temperature ferroelectricity dielectric constant ( ε r = 138.1) in...
The GaAs quantum dots (QDs) on an AlGaAs∕GaAs (111)A surface grown by a droplet epitaxy have density of 1.6×1011∕cm2, which is relatively higher than those (1.3×1010∕cm2) (001) surface. formation highly dense QDs the can be explained short migration Ga atoms. showed intense photoluminescence (PL) and narrower PL linewidth compared to that (001), indicating substrate high crystal quality uniformity (001).