Article
Chemistry, Physical
Tomas Zikmund, Jiri Bulir, Michal Novotny, Ladislav Fekete, Sergii Chertopalov, Stefan Andrei Irimiciuc, Mariana Klementova, Jarmila Balogova, Jan Lancok
Summary: This study reports on the formation of silver nanoparticles by gas aggregation in a reaction chamber at room temperature. The size distribution of the nanoparticles was analyzed using atomic force microscopy, while their physical shape and optical properties were characterized using scanning and transmission electron microscopy and spectral ellipsometry. The nanoparticles were then incorporated into various materials to study their influence on emission spectra and transmittance at different annealing temperatures.
Article
Chemistry, Multidisciplinary
He Huang, Hao Wang, Shasha Li, Jingyao Jiang, Yi Liu, Mingyang Cai, Lei Shao, Huanjun Chen, Jianfang Wang
Summary: This study demonstrates the construction of high-quality FP nanoresonators using gold nanodisks and a gold film, with WS2 flake sandwiched in between. The nanoresonators support FP resonances with different mode orders in the visible spectrum. The study also explores the interaction between FP modes and excitons in the WS2 spacer, allowing for modulation of WS2 indirect band gap emissions. The combination of plasmonic nanoparticles and FP resonators provides a promising platform for the development of compact nanophotonic devices.
Article
Chemistry, Multidisciplinary
Nicolli de Freitas, Bianca R. Florindo, Vitoria M. S. Freitas, Maria H. de O. Piazzetta, Carlos A. Ospina, Jefferson Bettini, Mathias Strauss, Edson R. Leite, Angelo L. Gobbi, Renato S. Lima, Murilo Santhiago
Summary: This research presents a simple and fast electrochemical thinning process to obtain ultra-large monolayer MoS2 on Au surfaces. The high affinity between MoS2 and Au enables the removal of bulk layers while preserving the first layer attached to the electrode. The study also explores the use of electrochemistry and optical microscopy for real-time observation of the thinning process, image treatment for estimating the thinning area and rate, and the preparation of free-standing MoS2 layers on microhole-structured Ni/Au meshes.
Article
Chemistry, Physical
Soungmin Bae, Tae Young Jeong, Hannes Raebiger, Ki-Ju Yee, Yong-Hoon Kim
Summary: We present spectroscopic evidence for the ultrafast trapping of band edge excitons at defects and the subsequent generation of defect-localized coherent phonons (CPs) in monolayer MoSe2. Our time-resolved pump-probe spectroscopy on the sub-picosecond time scale detects localized CPs only from the ultrafast exciton trapping at shallow traps. Based on density functional calculations, we identify the origins of deep and shallow traps as Se vacancy and oxygen molecule adsorbed on a Se vacancy, respectively. Our work establishes the correlations between defect-induced ultrafast exciton trapping and the generation of defect-localized CPs, providing new opportunities for engineering photoexcited carriers in two-dimensional materials through lattice defects.
NANOSCALE HORIZONS
(2023)
Article
Chemistry, Physical
Andre do Nascimento Barbosa, Cesar Augusto Diaz Mendoza, Yu Lei, Marco Giarola, Mauricio Terrones, Gino Mariotto, Fernando Lazaro Freire Junior
Summary: Defect engineering plays a crucial role in improving specific properties of two-dimensional materials. This study synthesized monolayer WS2 using chemical vapor deposition and introduced defects through Ar plasma treatment. The changes in properties were analyzed using various spectroscopy techniques, revealing the influence of defects on photoluminescence signal and providing a quantitative analysis of defect evolution in WS2 monolayers.
SURFACES AND INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Hee Seong Kang, Jung Hoon Kang, Sol Lee, Kihyun Lee, Do Hyoung Koo, Yong-Sung Kim, Young Joon Hong, Yong-Jin Kim, Kwanpyo Kim, Donghun Lee, Chul-Ho Lee
Summary: This study demonstrates the wafer-scale homogeneous growth and continuous bandgap tuning of WS2xSe2(1-x) alloys using metal-organic chemical vapor deposition. The optical bandgap of the alloys exhibits a nearly linear relationship with the chalcogen composition, indicating a low bowing effect. The fabrication of hetero-multilayers by stacking differently alloyed films is also successfully achieved.
NPG ASIA MATERIALS
(2022)
Article
Physics, Condensed Matter
Manvendra Singh Gangwar, Pratima Agarwal
Summary: The growth of metallic nanoparticles on solid substrates with desired shape and size is crucial for their application in solid-state devices. Solid state dewetting (SSD) technique offers a simple, low-cost method to fabricate metallic nanoparticles with control over shape and size on various substrates. In this study, silver nanoparticles (Ag NPs) were grown on Corning glass substrate using SSD of silver precursor thin film deposited at different temperatures. The influence of substrate temperature on the growth and properties of Ag NPs, including localized surface plasmon resonance (LSPR), photoluminescence (PL), and Raman spectroscopy, was investigated. The size of the NPs was found to vary from 25 nm to 70 nm with increasing substrate temperature. The LSPR peak position of Ag NPs shifted towards longer wavelengths at higher temperatures due to changes in particle size and interparticle separation. The PL spectra exhibited two bands corresponding to radiative interband transition and LSPR band of Ag NPs. Additionally, a strong Raman peak was observed at 1587 cm-1. The enhancement in PL and Raman peak intensity correlated with the LSPR of Ag NPs.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Nanoscience & Nanotechnology
Huanhuan Su, Shan Wu, Yuhan Yang, Qing Leng, Lei Huang, Junqi Fu, Qianjin Wang, Hui Liu, Lin Zhou
Summary: Research has found that the surface plasmon polariton (SPP)-assisted photoluminescence enhancement of MoS2 monolayer via a suspended periodic metallic (SPM) structure can achieve more than two orders of magnitude enhancement, primarily due to concentrated local field and quantum yield amplification. This method may provide a powerful way to boost two-dimensional exciton emission compared to nanoparticle-based geometries reported so far.
Article
Nanoscience & Nanotechnology
Huanhuan Su, Shan Wu, Yuhan Yang, Qing Leng, Lei Huang, Junqi Fu, Qianjin Wang, Hui Liu, Lin Zhou
Summary: In this study, a suspended periodic metallic (SPM) structure was used to achieve surface plasmon polariton (SPP)-assisted photoluminescence (PL) enhancement of MoS2 monolayer, providing more than two orders of magnitude enhancement without the need for metallic nanoparticle-based plasmonic geometries. The pronounced enhancement was attributed to concentrated local field of SPP enabled excitation rate increment and quantum yield amplification by the SPM nanostructure, showcasing a powerful way to boost two-dimensional exciton emission by plasmonic effects.
Article
Chemistry, Multidisciplinary
Yen-Ju Chiang, Tsan-Wen Lu, Pin-Ruei Huang, Shih-Yen Lin, Po-Tsung Lee
Summary: By combining a large-area MoS2 monolayer with silver plasmonic nanostructures in a deformable polydimethylsiloxane substrate, this study investigates the photoluminescence enhancement of MoS2 by surface lattice resonance modes of different silver plasmonic nanostructures. The stable photoluminescence enhancement of MoS2 by silver nanodisc arrays under varying stretching strains is observed, attributed to the mechanical holding effect of the MoS2 monolayer. The results suggest the possibility of stably enhancing the light emission of transition metal dichalcogenides using surface lattice resonance modes in a deformable platform.
Article
Optics
Nur Hidayah Azeman, Mohd Hafiz Abu Bakar, Nur Afifah Ahmad Nazri, Nadhratun Naiim Mobarak, Muhammad Asif Ahmad Khushaini, Tengku Hasnan Tengku Abdul Aziz, Ahmad Rifqi Md Zain, Ahmad Ashrif A. Bakar
Summary: This work reports the application of silver nanotriangles (AgNT) incorporated with chitosan/graphene oxide (Chit/GO) and carboxymethyl chitosan/graphene oxide (CMChit/GO) for the enhancement of ammonium localized surface plasmon resonance (SPR) sensor. The ammonium is detected through the hydrogen bonding between the hydroxyl functional group on the sensing material surface with ammonium. The results show that the addition of AgNT, Chit/GO, and CMChit/GO can improve the sensitivity of the sensor and effectively detect ammonium.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Suvarchala Vankudoth, Sunithabai Dharavath, Spoorthi Veera, Narsimhulu Maduru, Radhika Chada, Pavani Chirumamilla, Chaitanya Gopu, Shasthree Taduri
Summary: This study describes the green synthesis of silver nanoparticles using leaf extracts of Muntingia calabura, and characterizes their properties. The synthesized silver nanoparticles showed photoluminescence, antioxidant, anti-inflammatory, antidiabetic, and antibacterial effects.
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
(2022)
Article
Biochemistry & Molecular Biology
Suvarchala Vankudoth, Sunithabai Dharavath, Spoorthi Veera, Narsimhulu Maduru, Radhika Chada, Pavani Chirumamilla, Chaitanya Gopu, Shasthree Taduri
Summary: This study focuses on the green synthesis of silver nanoparticles using leaf extracts of Muntingia calabura, demonstrating various biological activities. The synthesized particles were characterized using multiple methods, showing potential applications in various fields.
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Gwangwoo Kim, Hyong Min Kim, Pawan Kumar, Mahfujur Rahaman, Christopher E. Stevens, Jonghyuk Jeon, Kiyoung Jo, Kwan-Ho Kim, Nicholas Trainor, Haoyue Zhu, Byeong-Hyeok Sohn, Eric A. Stach, Joshua R. Hendrickson, Nicholas R. Glavin, Joonki Suh, Joan M. Redwing, Deep Jariwala
Summary: Researchers have demonstrated a lithography-free method to create large areas of high-density localized emitters. By inducing strain in a WSe2 monolayer, high-density luminescence can be generated in the strained regions.
Article
Nanoscience & Nanotechnology
Bo Chu, Yan Li, Yiheng Qin, Taozheng Hu, Facheng Zhong, Fanguang Zeng, Pei Ding, Li Shao, Yinxiao Du, Shuo Tian, Zhuo Chen
Summary: We present a transparent display using a metasurface of silver nanoparticles (Ag NPs) consisting of a transparent substrate and a layer of Ag NPs deposited by a dielectric film. By a simple annealing process, the prepared Ag NPs metasurface shows a deep transmission valley at a wavelength of lambda = 468 nm, enabling transparent display by projecting monochromatic images. Truncated nanospheres formed by deposited Ag NPs exhibit directional scattering properties with a wide angular beamwidth of about 90 degrees, resulting in wide viewing angles and high brightness characteristics of the fabricated displays. The transmission modes can also be controlled by the thickness of the deposited dielectric film to achieve a red-shifted wavelength of lambda = 527 nm. This simple and low-cost approach using traditional thin film deposition and annealing techniques allows for scalable fabrication of transparent displays in large areas.
Editorial Material
Multidisciplinary Sciences
Soo Ho Choi, Seok Joon Yun, Yo Seob Won, Chang Seok Oh, Soo Min Kim, Ki Kang Kim, Young Hee Lee
Summary: This article discusses the importance of industrial-scale manufacturing of graphene and other 2D materials, as well as the limitations and opportunities for improvement of three state-of-the-art mass production techniques.
NATURE COMMUNICATIONS
(2022)
Review
Chemistry, Multidisciplinary
Eun-Mi Choi, Kyung Ik Sim, Kenneth S. Burch, Young Hee Lee
Summary: The proximity effect in heterostructures has great potential for customizable functionalities, but also faces challenges. The library of 2D vdW layered materials offers opportunities for tailoring versatile and more effective functionalities.
Article
Nanoscience & Nanotechnology
Sichen Wei, Yu Fu, Maomao Liu, Hongyan Yue, Sehwan Park, Young Hee Lee, Huamin Li, Fei Yao
Summary: This study presents a one-step solvothermal synthesis technique to construct a ternary hybrid structure consisting of dual-phase MoS2, MXene, and CNTs. The synergistic effects of active site exposure, surface area enlargement, and electrical conductivity improvement contribute to the enhanced performance and stability of the catalyst.
NPJ 2D MATERIALS AND APPLICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Van Tu Vu, Thanh Luan Phan, Thi Thanh Huong Vu, Mi Hyang Park, Van Dam Do, Viet Quoc Bui, Kunnyun Kim, Young Hee Lee, Woo Jong Yu
Summary: In this study, selective doping of Nb in a WS2-MoS2 lateral heterostructure was proposed, resulting in a transformation of the electrical behavior from N-N junction to P-N junction and P-N tunnel junction. By optimizing the structure, a photodiode with high rectification ratio and detectivity was achieved.
Article
Multidisciplinary Sciences
Dohyun Kim, Eui-Cheol Shin, Yongjoon Lee, Young Hee Lee, Mali Zhao, Yong-Hyun Kim, Heejun Yang
Summary: The study investigates the thermoelectric properties and phonon puddles in the charge density wave states in 1T-TaS2 using scanning thermoelectric microscopy. The authors observe counterintuitive variations in thermopower at the atomic scale due to the localization of valence electrons and their interlayer coupling. They also discover phonon puddles with a spatial range shorter than the conventional mean free path, revealing phonon propagation and scattering in the subsurface structures of 1T-TaS2.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Thanh Luan Phan, Sohyeon Seo, Yunhee Cho, Quoc An Vu, Young Hee Lee, Dinh Loc Duong, Hyoyoung Lee, Woo Jong Yu
Summary: In this article, the authors introduce a robust method for fabricating vertical 1D-0D-1D vdWI memories with ultra-small junction areas. The memories exhibit high performance and are achieved through cross-stacking carbon nanotubes.
NATURE COMMUNICATIONS
(2022)
Review
Chemistry, Multidisciplinary
Pramod Ghising, Chandan Biswas, Young Hee Lee
Summary: An alternative approach to charge-based electronics is to use the spin degree of freedom for information communication and processing. Graphene, with its long spin-diffusion length at room temperature, shows promise for highly scalable spintronics. The development of graphene spin valves has paved the way for spin devices in graphene, such as spin field-effect transistors and spin majority logic gates. This review examines the progress in graphene spin valves and their role in advancing spin logic devices, discussing different transport mechanisms and comparing the energy efficiency between graphene spin valves and charge-based field-effect transistors.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Ashok Mondal, Chandan Biswas, Young Hee Lee
Summary: Researchers have shown that the performance of transition-metal dichalcogenides phototransistors can be improved by fabricating the device on top of a distributed Bragg reflector (DBR). The DBR sample exhibited a significant enhancement in photoresponsivity ratio and photocurrent ratio compared to the SiO2 substrate sample, with transparent graphene electrode and hBN encapsulation.
Article
Chemistry, Multidisciplinary
Michael Neumann, Xu Wei, Luis Morales-Inostroza, Seunghyun Song, Sung-Gyu Lee, Kenji Watanabe, Takashi Taniguchi, Stephan Goetzinger, Young Hee Lee
Summary: The discovery of room-temperature single-photon emitters in two-dimensional hexagonal boron nitride has generated significant research interest. The origin of these emitters has been found to be organic molecules, possibly aromatic fluorophores. This finding has important implications for the understanding and utilization of single-photon emitters.
Article
Multidisciplinary Sciences
Ui Yeon Won, Quoc An Vu, Sung Bum Park, Mi Hyang Park, Van Dam Do, Hyun Jun Park, Heejun Yang, Young Hee Lee, Woo Jong Yu
Summary: In this study, multi-neuron connection is demonstrated using a multi-terminal floating-gate memristor (MT-FGMEM). The MT-FGMEM can accurately emulate membrane potential of neuron in multiple connections, with high on/off ratio and long retention time. Compared to conventional neurons, it significantly reduces energy consumption and enables training and classification similar to visual functions of the brain.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Matthew D. Watson, Alex Louat, Cephise Cacho, Sungkyun Choi, Young Hee Lee, Michael Neumann, Gideok Kim
Summary: Charge Density Waves (CDW) are investigated in Ta2NiSe7 using ARPES and the absence of nesting at the primary vector q is revealed, while backfolding at q and a possible nesting at 2q are observed. This suggests a peculiar charge density wave state in Ta2NiSe7 that cannot be easily explained by the Fermi surface nesting mechanism.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Eun-Mi Choi, Taesoo Kim, Byeong Wook Cho, Young Hee Lee
Summary: In this study, the interplay between spin-orbit coupling (SOC) and ferromagnetism in heterostructures of large-SOC and magnetic materials is investigated. The SOC-proximity effect on magnetic ordering in all-van der Waals-layered heterostructures is highlighted, resulting in various magnetic orderings induced at the interface. Additionally, a sharp magnetic switching from antiferromagnetic state to ferromagnetic state is observed, offering the possibility of interface-tailoring spintronics.
Article
Nanoscience & Nanotechnology
Ashok Mondal, Chandan Biswas, Sehwan Park, Wujoon Cha, Seoung-Hun Kang, Mina Yoon, Soo Ho Choi, Ki Kang Kim, Young Hee Lee
Summary: Researchers have developed a residue-free transfer method using polypropylene carbonate to transfer monolayer MoS2 onto a hexagonal boron nitride substrate at the centimetre scale. By incorporating a bismuth semimetal contact with an atomically clean monolayer MoS2 field-effect transistor, they achieved an ultralow Ohmic contact resistance and a record-high on/off ratio, making it an ideal platform for high-performance electrical devices using large-area transition metal dichalcogenides.
NATURE NANOTECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Riya Sebait, Roberto Rosati, Seok Joon Yun, Krishna P. Dhakal, Samuel Brem, Chandan Biswas, Alexander Puretzky, Ermin Malic, Young Hee Lee
Summary: This study reports the emergence of dark excitons in transition-metal-dichalcogenide heterostructures and explains their relationship with the stacking sequence. The researchers introduce the excitonic Elliot formula to explain this unusual stacking sequence and found that the intensity ratio of Q- to K-excitons is inversely proportional to laser power.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Lan-Anh T. Nguyen, Jinbao Jiang, Tuan Dung Nguyen, Philip Kim, Min-Kyu Joo, Dinh Loc Duong, Young Hee Lee
Summary: Magnetic fluctuations and random telegraph noise in vanadium-doped tungsten diselenide sandwiched between graphene layers can be electrically tuned. Bistable magnetic states are identified through random telegraph noise histogram and noise power spectrum analysis. Three categories of fluctuation are detected: small resistance fluctuations at high temperatures, large resistance changes over a wide range of temperatures, and persistent large resistance changes at low temperatures due to magnetic interlayer coupling.
NATURE ELECTRONICS
(2023)
