Zonghoon Lee
Ulsan National Institute of Science and Technology
Transmission electron microscopyNanotechnologyInorganic chemistryMaterials scienceGraphene
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Publications 192
Abstract Properties of metal elements can be modified by alloying. Given that catalytic efficiencies are often maximized using metal single-atoms (SAs), two immiscible metals can improve the catalytic activity when they can be present as non-agglomerated dual SAs. Here, we report yet-unexplored synthesis of high-performance electrocatalysts utilizing immiscibility of Cu/Ru bimetal atoms. In the synthesized electrocatalyst (Cu/Ru@GN), both Cu-SAs and Ru-SAs are dispersed on N-doped graphitic-matr...
1 CitationsSource
#1Wooyong Choi (UNIST: Ulsan National Institute of Science and Technology)
#2Jong Min Kim (KIST: Korea Institute of Science and Technology)
Last. Youngjoon Lim (KIST: Korea Institute of Science and Technology)
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Herein, we report for the first time the successful preparation of thiometallate-based precursors for use in a bottom-up synthetic process of supported Pt and PtNi nanoparticle catalyst. This precursor enabled the monodisperse synthesis of supported Pt nanoparticles and the in situ formation of S, which were caught directly in a collection system by the nanoparticle synthetic processes consisting of impregnation and thermal processes. S is proven to act as a capping agent in generating highly st...
#2Bo-Eun ParkH-Index: 1
Last. Hyungjun KimH-Index: 49
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Abstract We investigate effects of bottom electrodes on ZrO2 thin films formed through atomic layer deposition (ALD). We focus on the correlation between interfacial layer formation and electrical properties. For this comparative study, two different bottom electrodes consisting of TiN and Ru were employed. ALD ZrO2 films are deposited on these bottom electrodes by using tris(dimethylamino)cyclopentadielnyl zirconium ((C5H5)Zr[N(CH3)2]3) and ozone as a precursor and oxidant, respectively. Based ...
#1Aram YoonH-Index: 3
#2Jung Hwa KimH-Index: 8
Last. Zonghoon LeeH-Index: 34
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The electronic, catalytic, and optical properties of transition metal dichalcogenides (TMDs) are significantly affected by oxidation and using oxidation to tune the properties of TMDs has been actively explored. In particular, since transition metal oxides (TMOs) are promising hole injection layers, a TMD-TMO heterostructure can be potentially applied as a p-type semiconductor. However, the oxidation of TMDs has not been clearly elucidated due to the structural instability and the extremely smal...
#1Soo Yeon LimH-Index: 3
#2Jae-Ung Lee (Ajou University)H-Index: 2
Last. Hyeonsik CheongH-Index: 46
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Gallium selenide (GaSe) is one of the layered group-III metal monochalcogenides, which has an indirect bandgap in the monolayer and a direct bandgap in bulk unlike other conventional transition metal dichalcogenides (TMDs) such as MoX2 and WX2 (X = S and Se). Four polytypes of bulk GaSe, designated as beta-, epsilon-, gamma-, and delta-GaSe, have been reported. Since different polytypes result in different optical and electrical properties even with the same thickness, identifying the polytype i...
#1Seunguk Song (UNIST: Ulsan National Institute of Science and Technology)H-Index: 2
#2Yeoseon Sim (UNIST: Ulsan National Institute of Science and Technology)H-Index: 2
Last. Yinan Liu (PKU: Peking University)H-Index: 1
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A key challenge in the development of two-dimensional (2D) devices is the fabrication of metal–semiconductor junctions with minimal contact resistance and depinned energy levels. An ideal solution for practical applications is to make contacts between 2D van der Waals semiconductors and 2D van der Waals metals. Here we report the wafer-scale production of patterned layers of metallic transition metal ditellurides on different substrates. Our tungsten ditelluride and molybdenum ditelluride layers...
1 CitationsSource
#1Shahana ChatterjeeH-Index: 7
#2Na Yeon KimH-Index: 7
Last. Rodney S. RuoffH-Index: 3
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Principal defects found in graphite films include grain boundaries and wrinkles. These defects are well known to have detrimental effects on properties such as thermal and electrical conductivities...
#1Fabian Schütt (CAU: University of Kiel)H-Index: 10
#2Maximilian Zapf (FSU: University of Jena)H-Index: 3
Last. Tian Carey (University of Cambridge)H-Index: 5
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Laser diodes are efficient light sources. However, state-of-the-art laser diode-based lighting systems rely on light-converting inorganic phosphor materials, which strongly limit the efficiency and lifetime, as well as achievable light output due to energy losses, saturation, thermal degradation, and low irradiance levels. Here, we demonstrate a macroscopically expanded, three-dimensional diffuser composed of interconnected hollow hexagonal boron nitride microtubes with nanoscopic wall-thickness...
#1Jungmin Park (UNIST: Ulsan National Institute of Science and Technology)H-Index: 6
#2Inseon Oh (UNIST: Ulsan National Institute of Science and Technology)H-Index: 1
Last. Hosub Jin (UNIST: Ulsan National Institute of Science and Technology)H-Index: 23
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The pristine graphene described with massless Dirac fermion could bear topological insulator state and ferromagnetism via the band structure engineering with various adatoms and proximity effects from heterostructures. In particular, topological Anderson insulator state was theoretically predicted in tight-binding honeycomb lattice with Anderson disorder term. Here, we introduced physi-absorbed Fe-clusters/adatoms on graphene to impose exchange interaction and random lattice disorder, and we obs...
#1Hyo Ju Park (UNIST: Ulsan National Institute of Science and Technology)H-Index: 10
#2Janghwan Cha (Sejong University)H-Index: 4
Last. Zonghoon Lee (UNIST: Ulsan National Institute of Science and Technology)H-Index: 34
view all 9 authors...
Hexagonal boron nitride (hBN) is an insulating two-dimensional (2D) material with a large bandgap. Although known for its interfacing with other 2D materials and structural similarities to graphene, the potential use of hBN in 2D electronics is limited by its insulating nature. Here, we report atomically sharp twin boundaries at AA′/AB stacking boundaries in chemical vapor deposition–synthesized few-layer hBN. We find that the twin boundary is composed of a 6′6′ configuration, showing conducting...