A5027544287- Semiconductor Quantum Structures and Devices
- Advanced Semiconductor Detectors and Materials
- Quantum Dots Synthesis And Properties
- Advanced Photocatalysis Techniques
- 2D Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Graphene research and applications
- Copper-based nanomaterials and applications
- Neuroscience and Neural Engineering
- Semiconductor Lasers and Optical Devices
- Advanced Memory and Neural Computing
- ZnO doping and properties
- MXene and MAX Phase Materials
- Photoreceptor and optogenetics research
- Semiconductor materials and devices
- Synthesis and properties of polymers
- Graphene and Nanomaterials Applications
- Diamond and Carbon-based Materials Research
- Gas Sensing Nanomaterials and Sensors
- Conducting polymers and applications
- Nanowire Synthesis and Applications
- Advanced Battery Materials and Technologies
- TiO2 Photocatalysis and Solar Cells
- Ga2O3 and related materials
- Perovskite Materials and Applications
Chungnam National University
2016-2025
Seoul National University Bundang Hospital
2021-2022
Seoul National University
2006-2018
Daejeon University
2017
Materials Science & Engineering
2013
Institute for Basic Science
2013
Korean Intellectual Property Office
2012
Seoul National University Hospital
2008
BioElectronics (United States)
2005-2008
University of Southern California
2001-2006
Polymers for IR imaging: The preparation of high refractive index polymers (n = 1.75 to 1.86) via the inverse vulcanization elemental sulfur is reported. High quality imaging in near (1.5 μm) and mid-IR (3–5 regions using polymeric lenses from these materials was demonstrated. As a service our authors readers, this journal provides supporting information supplied by authors. Such are peer reviewed may be re-organized online delivery, but not copy-edited or typeset. Technical support issues...
Sulfur-rich copolymers based on poly(sulfur-random-1,3-diisopropenylbenzene) (poly(S-r-DIB)) were synthesized via inverse vulcanization to create cathode materials for lithium-sulfur battery applications. These exhibit enhanced capacity retention (1005 mAh/g at 100 cycles) and lifetimes over 500 cycles a C/10 rate. poly(S-r-DIB) represent new class of polymeric electrode that one the highest charge capacities reported, particularly after extended charge-discharge cycling in Li-S batteries.
Abstract With the demand for low‐power‐operating artificial intelligence systems, bio‐inspired memristor devices exhibit potential in terms of high‐density memory functions and emulation synaptic dynamics human brain. The 2D material MXene attracts considerable interest use resistive‐switching synapse owing to its excellent physicochemical properties devices. However, few memristive that display increased switching performances are reported, with no significant results. Herein, conductivity...
We report a high detectivity of 3×1011 cm Hz1/2/W at 78 K for normal-incidence quantum dot infrared photodetectors with ten layers undoped InAs/InGaAs/GaAs active regions. The seen 1.4 V corresponds to photoresponse peaks 9.3 and 8.7 μm positive negative bias, respectively.
Abstract Polysulfide dissolution into the electrolyte and poor electric conductivity of elemental sulfur are well‐known origins for capacity fading in lithium–sulfur batteries. Various smart electrode designs have lately been introduced to avoid these mechanisms, most which demonstrate significantly improved cycle life. Nevertheless, an in‐depth understanding on effect microstructure nanoscale electron transport near is currently lacking. In this study, authors report organized nanocomposite...
We have performed a comprehensive investigation of n-type quantum dot infrared photodetectors (QDIPs) based on InAs/GaAs epitaxical island dots (QDs) grown via the innovative punctuated growth technique. The structural properties QDs were investigated with cross-sectional transmission electron microscopy and atomic force microscopy. electronic inserted in QDIP devices photoluminescence (PL), PL excitation, intra- inter-band photocurrent spectroscopy. influence AlGaAs layers into active...
A novel synthetic and processing strategy for converting elemental sulfur into polymeric nanocomposite materials is reported. We describe a facile one-pot reaction using oleylamine as comonomers to prepare high content copolymers lead sulfide nanoparticle (PbS NP) nanocomposites. This process enables the preparation of solution processable nanocomposites, where loading dispersion PbS NP inclusions could be precisely controlled. demonstrate dual roles with both copolymerization well in situ...
We report on the fabrication of wholly polymeric one-dimensional (1-D) photonic crystals (i.e., Bragg reflectors, mirrors) via solution processing for use in near (NIR) and short wave (SWIR) infrared spectrum (1-2 μm) with very high reflectance (R ∼ 90-97%). Facile these highly reflective films was enabled by direct access to processable, ultrahigh refractive index polymers, termed, Chalcogenide Hybrid Inorganic/Organic Polymers (CHIPs). The (n) CHIPs materials (n = 1.75-2.10) allowed...
Abstract A controllable approach that combines surface plasmon resonance and two-dimensional (2D) graphene/MoS 2 heterojunction has not been implemented despite its potential for efficient photoelectrochemical (PEC) water splitting. In this study, plasmonic Ag-decorated 2D MoS nanosheets were vertically grown on graphene substrates in a practical large-scale manner through metalorganic chemical vapor deposition of thermal evaporation Ag. The yielded up to 10 times higher photo-to-dark...
To develop a liquid crystal polymer (LCP)-based, long-term implantable, retinal stimulation microelectrode array using novel fabrication method.The process used laser micromachining and customized thermal-press bonding to produce LCP-based arrays. evaluate the resultant electrode arrays, in vitro reliability tests vivo animal experiments were performed. The consisted of site impedance recording interlayer adhesion monitoring during accelerated soak tests. For testing, fabricated arrays...
Get yellow: The utilization of elemental sulfur as an unconventional medium for the synthesis and stabilization colloidal gold is reported. In this system, serves multiple functions to sulfurate PPh3, solubilize reduce AuI precursors into Au nanoparticles (NPs; see picture). Direct vulcanization dispersions AuNPs afforded cross-linked nanocomposites confirmed by TEM, XRD, XPS, Raman spectroscopy. Detailed facts importance specialist readers are published ”Supporting Information”. Such...
High-quality graphene was synthesized on Cu foil using inductively-coupled plasma chemical vapor deposition (ICPCVD). ICP is very effective, such that a few-layer could be formed within few seconds. However, the thickness gradually decreased by increasing growth time and power, finally being saturated at single layer. The quality also significantly enhanced preferential etching of structurally-disordered C structures, followed newly Understanding ICPCVD kinetics, governed formation atoms H...
The purpose of our study is to evaluate the biocompatibility various polymers used as microelectrode arrays (MEAs) in retinal prostheses through vitro cytotoxicity testing following a standardizedThree types polymer-based MEAs were examined: silicone-based platinum, polyimide-based gold and liquid crystal polymer (LCP)-based MEAs. silicone/platinum fabricated by Nd:YAG laser, polyimide/gold semiconductor manufacturing technique, LCP/gold laser micromachining thermal-bonding process. All...
We successfully demonstrated the improvement and stabilization of electrical properties a graphene field effect transistor by fabricating sandwiched amorphous boron nitride (a-BN)/graphene (Gr)/a-BN using directly grown a-BN film. The film was via low-pressure chemical vapor deposition (LPCVD) at low growth temperature 250 °C applied as protection layer in structure. Both structural states as-grown were verified various spectroscopic microscopic analyses. analyzed Raman spectra Gr/SiO2...
Constructing pertinent nanoarchitecture with abundant exposed active sites is a valid strategy for boosting photocatalytic hydrogen generation. However, the controllable approach of an ideal architecture comprising vertically standing transition metal chalcogenides (TMDs) nanosheets on 3D graphene network remains challenging despite potential efficient production. In this study, we fabricated edge-rich structuring photocatalysts involving grown TMDs porous framework (referred to as Gr). 2D...
Advances in the semiconductor industry have been limited owing to constraints imposed by silicon-based CMOS technology; hence, innovative device design approaches are necessary. This study focuses on "more than Moore" approaches, specifically neuromorphic computing. Although MoS2 devices attracted attention as computing candidates, their performances due environment-induced perturbations carrier dynamics and formation of defect states. explores integration hydrocarbon (HC) layers onto active...
We report InAs quantum dot infrared photodetectors that utilize In0.15Ga0.85As strain-relief cap layers. These devices exhibited normal-incidence photoresponse peaks at 8.3 or 8.8 μm for negative positive bias, respectively. At 77 K and −0.2 V bias the responsivity was 22 mA/W peak detectivity D* 3.2×109 cm Hz1/2/W.
We report on tailoring detection bands of InAs quantum-dot infrared photodetectors (QDIPs) using InxGa1−xAs strain-relieving capping layers that also act as quantum wells (QWs). QDIPs with QDs capped by a 20 ML In0.15Ga0.85As QW show sharp photoresponse at ∼9 μm, while the counterpart without QWs broad in 5–7 μm range. The excited states involved intraband transitions appear to be coupled QD and electron states.
We report the realization of electron intraband absorption based middle- (∼5.6 μm) and long- (∼10 wavelength infrared (IR) photoresponse for normally incident radiation on InGaAs-capped GaAs(001)/InAs quantum dots (QDs) in a n–i(QD)–n structure. The relative this dual-wavelength structure is tunable up to two orders magnitude with bias. full width at half maximum long-wavelength IR photocurrent peak 80 K as narrow 8.2 meV.