Article
Materials Science, Multidisciplinary
Yeonghun Lee, Yaoqiao Hu, Dongwook Kim, Suman Datta, Kyeongjae Cho
Summary: In this study, a new method was developed to predict carrier mobility in amorphous semiconductors using first-principles calculations, and the validity of this method was confirmed through quantitative comparisons with experimental data. Localization analysis provided further insights into the distinct features between amorphous metal oxides and amorphous silicon.
Article
Materials Science, Multidisciplinary
Lingchun Jia, Yingli Chang, Ge Song, Xiaolin Liu, Mu Gu, Jiajie Zhu
Summary: CuI has gained attention for optoelectronic devices because of its wide band gap. This study investigates the diffusion and electronic properties of CuI doped with various elements using first-principles calculations. Doping with Br, Cl, and F significantly reduces the band gap, and anion at the interstitial site introduces unoccupied states, enhancing p-type conductivity.
RESULTS IN PHYSICS
(2022)
Article
Environmental Sciences
Yubo Zhao, Kexun Li, Bangsong Sheng, Feiyong Chen, Yang Song
Summary: Fluorine pollution in wastewater is a global environmental issue. Nitrogen-doped core-shell mesoporous carbonaceous nanospheres (NMCS) were developed to enhance the defluorination performance in capacitive deionization systems. The maximum electrosorption capacity of NMCS for fluorine was 13.34 mg g(-1), 24% higher than the undoped counterpart. NMCS also exhibited excellent repeatability with little decrease in electrosorption capacity after 10 adsorption-regeneration cycles. The doping of nitrogen improved the physicochemical properties of NMCS, resulting in enhanced defluorination performance.
Article
Chemistry, Physical
Juan Sun, Bin Zhang, Wenxin Chen, Zichen Tao, Jie Liu, Lidong Wang
Summary: In this study, a carbon-rich g-C3N4 with nitrogen vacancies (CCN4) was synthesized by incorporating biochar into g-C3N4. The doped carbon atoms enhanced the delocalization pi states and improved the charge separation and migration. The CCN4 catalyst exhibited excellent photocatalytic hydrogen evolution reaction (HER) activity, with a hydrogen evolution rate 5.1 times higher than that of pristine g-C3N4 (PCN). Moreover, CCN4 showed good resistance to salt, indicating its potential for practical applications.
Article
Spectroscopy
Yujing Nie, Shuhan Wang, Youxiu Lin, Wenqiang Lai, Wen Weng, Dianping Tang
Summary: A novel fluorescent probe was developed for the detection of ClO- ions with high sensitivity and selectivity in aqueous media. This nitrogen-fluorine co-doped nanodot probe showed fast quenching response and low limit of detection, making it promising for the analysis of pollutants.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Chemistry, Physical
Pei Yao, Yu Song, Xu Zuo
Summary: This study investigates the migration barriers and formation energies of silicon interstitials at an amorphous-SiO2/Si interface. Results show that neutral interstitial defects may enter the interface via low-barrier channels but are trapped due to high energy barriers for reverse migration. Additionally, the stable configuration of interstitial silicon at the interface depends on the relative positions of the Fermi level and interfacial strain.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Tingting Liang, Jingpei Xie, Aiqin Wang, Douqin Ma, Zhiping Mao, Jian Wang, Haisheng Li
Summary: This study investigated the effects of atom doping on the structural characteristics and hydrogen evolution reaction (HER) performance of black phosphorene (BP), a potential electrocatalyst material. The results showed that the doping of metal atoms, especially Fe, improved the electronic properties and significantly enhanced the HER performance. This research provides theoretical significance for the design of high-efficiency HER electrocatalysts.
APPLIED SURFACE SCIENCE
(2022)
Article
Electrochemistry
Dandan Liu, Jingyi Wang, Zhexuan Li, Zimeng Yun, Yongsheng Zhang, Jiajia Huang
Summary: This study explores the use of nitrogen-rich ultrathin carbon nanosheets as the anode material for potassium ion batteries. The resulting batteries exhibit high specific capacity and excellent long-term stability, providing a new strategy for reversible potassium ion storage.
ELECTROCHIMICA ACTA
(2022)
Article
Engineering, Electrical & Electronic
Yulin Liu, Zhengrong Zhu, Yongqi Liu, Jiang Wu, Yang Ling, Zijian Xiang, Shuai Qin, Yubowen Ye, Mengjie Bai
Summary: Bismuth oxide iodate photocatalyst is limited in its applications due to its large band gap. Doping nonmetallic sulfur atoms into the BiOIO3 semiconductor can reduce the energy band gap and enhance photocatalytic activity. Doping at oxygen sites can move the conduction band position down, while iodine site doping can introduce impurity states that act as a bridge for electron transition. This study provides insights for improving photocatalytic performance through crystal doping modification.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Materials Science, Ceramics
Murat Durandurdu
Summary: A boron-substituted amorphous graphite network with a layered structure primarily composed of hexagonal rings is generated through first principles molecular dynamics simulation. The network exhibits a semimetal character and has mechanical properties comparable to graphite or amorphous graphite.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2022)
Article
Chemistry, Physical
Yiqun Chen, Guochang Li, Yu Zeng, Lijie Yan, Xizhang Wang, Lijun Yang, Qiang Wu, Zheng Hu
Summary: By stabilizing the Fe3+ sites, F-doped Fe-N-C single-site catalysts can enhance the efficiency of CO2RR. The stabilized Fe3+ sites promote CO2RR, suppress competing hydrogen evolution reaction, and increase the electroactive surface area and charge transfer.
Article
Chemistry, Multidisciplinary
Yun-Ho Kang, Sangbong Lee, Youngwoo Choi, Won Kyung Seong, Kyu Hyo Han, Jang Hwan Kim, Hyun-Mi Kim, Seungbum Hong, Sun Hwa Lee, Rodney S. Ruoff, Ki-Bum Kim, Sang Ouk Kim
Summary: This study tests a reliable method for preparing a conformal amorphous carbon (a-C) layer with a thickness at the nanometer level, as a potential diffusion barrier layer for miniaturization of next-generation ultrahigh-density semiconductor devices. The results show that the a-C barrier has a better blocking effect on copper diffusion than the conventional tantalum nitride barrier.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Inorganic & Nuclear
Manasa Sunku, Ravi Gundeboina, C. H. Shilpa Chakra, Vimala Kaniki Reddy, M. Vithal
Summary: This study presents a reliable design of a nitrogen and carbon doped CoSb2O6 photocatalyst for the efficient degradation of dye-contaminated water, showing remarkable photodegradation activities of up to 99% in 120 mins under visible light irradiation.
INORGANIC CHEMISTRY COMMUNICATIONS
(2021)
Article
Nanoscience & Nanotechnology
Fredy R. Zypman
Summary: The dielectric properties of materials are often introduced using empirical values, but it is important to have theoretical frameworks to predict and compute these values. A theoretical model is presented here to gain insight into the microscopic origin of permittivity, considering atomic polarization and the assembly of atoms in a periodic arrangement. Explicit formulas for permittivity and numerical results are developed within this model.
Article
Chemistry, Physical
Ziyang Zhang, Liming Liu, Canhui Xu, Shuanglin Hu
Summary: The hydrogen adsorption and diffusion behaviors on clean and doped Zr(0001) surfaces were studied using first-principles calculations. It was found that most dopants promote hydrogen adsorption on next nearest neighbor sites and enhance hydrogen diffusion on the surface plane and penetration into subsurface layers. Element doping may facilitate hydride nucleation in Zr alloys.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Nanoscience & Nanotechnology
Gyeong Hee Ryu, Sungwoo Lee, Jung Hwa Kim, Gun-Do Lee, Zonghoon Lee
Summary: The study reveals that oxygen and hydrogen atoms can participate in the formation of point defects in freestanding graphene monolayers. The theoretical calculations demonstrate that these participating atoms can stabilize 13-5 ring pairs under electron beam irradiation.
Article
Nanoscience & Nanotechnology
Yung-Chang Lin, Sungwoo Lee, Yueh-Chiang Yang, Po-Wen Chiu, Gun-Do Lee, Kazu Suenaga
Summary: This study demonstrates the unambiguous observation of a two-dimensional IF bilayer grown on the surface of WSe2, showing a clear hexagonal lattice and robust epitaxial relationship with the substrate. Despite the known instability of IF at room temperature, it was found stabilized on a suitable substrate, pointing to the possibility of producing unexpected crystalline structures.
NPJ 2D MATERIALS AND APPLICATIONS
(2021)
Article
Chemistry, Physical
Geosan Kang, Deokgi Hong, Ji-Yong Kim, Gun-Do Lee, Sungwoo Lee, Dae-Hyun Nam, Young-Chang Joo
Summary: The study presents a method for achieving polymorphic conversion of VIB TMDs using gas-solid reactions, with process conditions predicted by thermodynamic calculations and the mechanism triggered by the formation of S vacancy (V-S).
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Byungsoo Kim, Duyoung Yang, Woonbae Sohn, Seungmin Lee, Hwan-Hee-Chan Choi, Taehoon Jang, Euijoon Yoon, Yongjo Park, Ho Won Jang
Summary: The use of compositionally graded α-(AlxGa1-x)2O-3 layers reduces threading dislocations and improves the crystalline quality of epitaxial α-Ga2O3 films. The strain relaxation and dislocation inclination in the graded α-(AlxGa1-x)2O-3 layers were confirmed through reciprocal space mapping and transmission electron microscopy studies. Dislocations annihilation in the graded α-(AlxGa1-x)2O-3 layers led to a significant reduction (64.9%) in the density of threading dislocations in α-Ga2O3 films compared to those grown directly on a sapphire substrate.
Article
Nanoscience & Nanotechnology
Hwanyeol Park, Dong-Hoon Han, Hong Taek Lim, Woojin Choi, Ho Jun Kim
Summary: This study investigates the thermodynamic driving force and phase transition mechanism of tungsten-alumina heterostructures using first-principles methods. The results show that amorphous tungsten films maintain a conformal coverage at nanoscale (0.7 nm) until the thickness exceeds this value.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Physical
Soon Hyeong So, Sungwoo Lee, Jungho Mun, Junsuk Rho, Chong Rae Park
Summary: Researchers have discovered an abnormal phenomenon of hydrogen storage in carbon nanopores and proposed a hypothesis of intrinsicelectromagnetic field (IEMF) interaction. They found that even without an external electromagnetic field, neutral carbon nanopores could form a significant IEMF and confirmed the difference of IEMF inside and outside the nanopores. This difference influences the hydrogen storage in the carbon nanopores. This finding will shed light on other abnormal phenomena related to nanopores with sub-1 nm diameters.
Article
Nanoscience & Nanotechnology
Yong-Hee Lee, Duyoung Yang, Byeongjun Gil, Mi-Hyang Sheen, Euijoon Yoon, Yongjo Park, Ho-Won Jang, Sangmoon Yoon, Miyoung Kim, Young-Woon Kim
Summary: This study investigated the microstructure characteristics of high-quality alpha-Ga2O3 thin film grown on the Al2O3 single crystal substrate membrane. Hetero-epitaxial alpha Ga2O3 crystals exhibit a three-fold symmetry during the initial stage of growth due to the oxygen template provided by Al2O3. Inversion domains with a 180° inverted configuration compared to the surrounding environment were observed, leading to additional diffraction spots along the [110] and [010] directions.
Article
Nanoscience & Nanotechnology
Yong-Hee Lee, Byeongjun Gil, Duyoung Yang, Mi-Hyang Sheen, Euijoon Yoon, Yongjo Park, Ho-Won Jang, Sangmoon Yoon, Miyoung Kim, Young-Woon Kim
Summary: This study explores the relationship between atomic arrangement and luminescence properties in a high-quality α-Ga2O3 thin film on an Al2O3 single-crystal membrane. The strain induced by merging domain boundaries shows significant variability in annular darkfield images, despite no confirmed additional gallium concentration. The bandgap energy of α-Ga2O3 is estimated to be 5.56 eV from CL measurement in a transmission electron microscope. A peak at 320 nm is observed within the domain, while the domain boundary exhibits spectrum peaks at 380-480 nm. The formation of anti-phase domains (APD) is caused by the instabilities of Al-O bonding templates provided by the Al2O3 substrate. The APD boundary results in a characteristic wavelength of 350 nm, which arises from the merging boundary of in-phase and anti-phase domains.
Article
Chemistry, Multidisciplinary
Matthew J. Coupin, Yi Wen, Sungwoo Lee, Anshul Saxena, Colin Ophus, Christopher S. Allen, Angus I. Kirkland, Narayana R. Aluru, Gun-Do Lee, Jamie H. Warner
Summary: Defects in crystalline lattices cause modulation of the atomic density, leading to variations in the associated electrostatics at the nanoscale. Four-dimensional scanning transmission electron microscopy (4D-STEM) was used to measure electric fields near point dislocations in a monolayer, overcoming the challenges of traditional phase contrast imaging. The increased electric field magnitude near the (1,0) edge dislocation core in graphene is shown to arise from long-range interactions beyond the nearest atomic neighbor. These results provide insights into using 4D-STEM for quantifying electrostatics and mapping potential variations in thin materials.
Article
Chemistry, Physical
Yeji Baek, Hakhyeon Song, Deokgi Hong, Suneon Wang, Sungwoo Lee, Young-Chang Joo, Gun-Do Lee, Jihun Oh
Summary: The electrochemical conversion of CO2 to ethanol and ethylene is a promising method for addressing global climate change. CuZn alloys as catalysts enhance the ethanol selectivity and achieve high ethanol production efficiency.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Nanoscience & Nanotechnology
Sungwoo Lee, Deokgi Hong, Ji-Yong Kim, Dae-Hyun Nam, Sungwoo Kang, Seungwu Han, Young-Chang Joo, Gun-Do Lee
Summary: The study presents a detailed atomic-scale mechanism of structural phase transition of MoS2 nanocrystals under reaction with CO gas molecules. The research findings suggest that the evaporation of S atoms at the edge induces the structural change from 2H to 1T/1T' in the basal plane of nanocrystals.
ACS APPLIED NANO MATERIALS
(2021)