Mun Seok Jeong
Hanyang University 신소재공학부 · Materials Science
Mun Seok Jeong 교수의 연구실은 2차원 물질과 양자점, 나노소재를 기반으로 한 나노광전자 소자에 초점을 맞추고 있습니다. 특히 단일층 텅스텐 디 tellur화물, 모리브덴 디 sulfide 등 전이금속 디 chalcogenide의 광전 특성 향상과 하이브리드 구조 설계를 통해 고성능 광검출기, 태양전지, 발광소자 등 응용 기술을 개발하고 있습니다. 전자기기의 효율을 높이기 위한 표면 플라스몬, 전자적 제어, 결함 제어 기술 등도 핵심 연구 주제입니다.
Figures are computed from collected data and may differ slightly.
Hybrid structures of two-dimensional (2D) materials and quantum dots (QDs) are particularly interesting in the field of nanoscale optoelectronic devices because QDs are efficient light absorbers and can inject photocarriers into thin layers of 2D transition-metal dichalcogenides, which have high carrier mobility. In this study, we present a heterostructure that consists of a monolayer of tungsten diselenide (ML WSe<sub>2</sub>) covered by nitrogen-doped graphene QDs (N-GQDs). The improved photol
Monolayer tungsten disulfide (WS<sub>2</sub>) has emerged as an active material for optoelectronic devices due to its quantum yield of photoluminescence. Despite the enormous research about physical characteristics of monolayer WS<sub>2</sub>, the defect-related Raman scattering has been rarely studied. Here, we report the correlation of topography and Raman scattering in monolayer WS<sub>2</sub> by using tip-enhanced resonance Raman spectroscopy and reveal defect-related Raman modes denoted as
Monolayer (1L) transition metal dichalcogenides (TMDCs) are promising materials for nanoscale optoelectronic devices because of their direct band gap and wide absorption range (ultraviolet to infrared). However, 1L-TMDCs cannot be easily utilized for practical optoelectronic device applications (e.g., photodetectors, solar cells, and light-emitting diodes) because of their extremely low optical quantum yields (QYs). In this investigation, a high-gain 1L-MoS<sub>2</sub> photodetector was successf
We study the electronic and optoelectronic properties of a broken-gap heterojunction composed of SnSe<sub>2</sub> and MoTe<sub>2</sub> with gate-controlled junction modes. Owing to the interband tunneling current, our device can act as an Esaki diode and a backward diode with a peak-to-valley current ratio approaching 5.7 at room temperature. Furthermore, under an 811 nm laser irradiation the heterostructure exhibits a photodetectivity of up to 7.5 × 10<sup>12</sup> Jones. In addition, to harnes
We demonstrate the pulsed voltage tunable multileveled resistive switching (RS) across a promising transparent energy material of (C<sub>4</sub>H<sub>9</sub>NH<sub>3</sub>)<sub>2</sub>PbBr<sub>4</sub>. The X-ray diffraction and scanning electron microscopy results confirm the growth of (001) plane-orientated nanostructures of (C<sub>4</sub>H<sub>9</sub>NH<sub>3</sub>)<sub>2</sub>PbBr<sub>4</sub> with an average size of ∼360 nm. The device depicts optical transmittance higher than 70% in the visi
Abstract The improvement of the light extraction efficiency (LEE) of a conventional InGaN blue light‐emitting diode (LED) by the incorporation of one‐dimensional ZnO sub‐microrods is reported. The LEE is improved by 31% through the wave‐guiding effect of ZnO sub‐microrods compared to LEDs without the sub‐microrods. Different types of ZnO microrods/sub‐microrods are produced using a simple non‐catalytic wet chemical growth method at a low temperature (90 °C) on an indium‐tin‐oxide (ITO) top conta
Spatially and spectrally resolved photoluminescence (PL) from InGaN/GaN quantum wells is obtained using near-field scanning optical microscopy (NSOM). Samples displaying high macroscopic PL intensity revealed nonuniform intensity and linewidth but nearly uniform peak position. It suggests that the contrast in the NSOM image reflects nonuniform distribution of dislocations or defects which act as nonradiative recombination centers. The formation of quantum dots with size of 30±25 nm and their siz
We report high-quality GaN crystals grown directly on graphene layers without a buffer layer by metal–organic chemical vapour deposition.
The bilayer grain boundaries (GBs) in chemical-vapor-deposition-grown large-area graphene are identified using multispectral tip-enhanced Raman imaging with 18 nm spatial resolution. The misorientation angle of the bilayer GBs is determined from a quantitative analysis of the phonon-scattering properties associated with the modified electronic structure.
Two-dimensional transition-metal dichalcogenides (TMDCs) are notable materials owing to their flexibility, transparency, and appropriate bandgaps. Because of their unique advantages, TMDC p-n diodes have been studied for next-generation electronics and optoelectronics. However, their efficiency must be increased for commercialization. In this study, we demonstrated a heterostructure composed of few-layer ReS2 and WSe2. This few-layer ReS2/WSe2 heterostructure exhibits a p-n junction and an n-n j
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