Article
Physics, Applied
Irene Geijselaers, Neimantas Vainorius, Sebastian Lehmann, Craig E. Pryor, Kimberly A. Dick, Mats-Erik Pistol
Summary: The study demonstrated the optical properties of highly controlled wurtzite-zinc blende GaAs quantum dots and nanowires with a single interface, showing sharp luminescence signals and 0D states, indicating the potential of polytype quantum dots for physics and optics applications.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Bertram Schulze Lammers, Damla Yesilpinar, Alexander Timmer, Zhixin Hu, Wei Ji, Saeed Amirjalayer, Harald Fuchs, Harry Monig
Summary: Controlling the identity of the tip-terminating atom or molecule in low-temperature atomic force microscopy has led to significant advances in surface chemistry and nanotechnology. Comparing four atomically defined tips, it was found that Cu-tips react with surface oxygen, while Xe and CO tips allow for increased resolution due to their chemical inertness. CuOx-tips, with higher rigidity and selectively increased chemical reactivity, prevent tip-bending artifacts and generate a distinct chemical contrast, which holds promise for future studies on metal-oxide surfaces.
Review
Chemistry, Physical
Andrey Baydin, Fuyang Tay, Jichao Fan, Manukumara Manjappa, Weilu Gao, Junichiro Kono
Summary: This article discusses the applications of carbon nanotubes in quantum technology. Carbon nanotubes possess one-dimensional electronic states, excitons, and phonons, which make them suitable for developing quantum devices with high operating temperatures. The article covers the fundamental properties of carbon nanotubes, their growth and purification methods, and methodologies for assembling them into structures that exhibit macroscopic quantum properties. Most importantly, recent developments and proposals for quantum information processing devices based on individual and assembled nanotubes are reviewed.
Article
Chemistry, Physical
Bo Tang, Shi-Cheng Zhu, Hao Liang, Shen Li, Bi-Jian Liu, Fang-Xing Xiao
Summary: In recent years, metal nanoclusters have shown great potential in solar energy conversion due to their unique atomic stacking arrangements and quantum size effect. However, their short carrier lifetimes and poor stabilities have hindered the development of robust metal nanocluster-based photosystems. In this study, a multilayered photoanode with a highly efficient spatially directional charge transport pathway was designed using positively charged poly(diallyl-dimethylammonium chloride) and tailor-made negatively charged l-glutathione-capped Ag-x nanoclusters. This design achieved enhanced photoelectrochemical water oxidation performance under visible light irradiation by reducing charge recombination and prolonging carrier lifetime.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Chemistry, Multidisciplinary
Rui Ding, Yawen Chen, Xiaoke Li, Zhiyan Rui, Kang Hua, Yongkang Wu, Xiao Duan, Xuebin Wang, Jia Li, Jianguo Liu
Summary: Renewably produced hydrogen is vital for achieving a low-carbon energy economy. By developing catalysts with atomically dispersed low-coordinate Co-N sites, the study demonstrates high catalytic activity and durability in hydrogen evolution reaction. This new concept provides a promising approach to reducing the cost of hydrogen production in the future.
Article
Multidisciplinary Sciences
Rui Xu, Zhiqiang Zeng, Yong Lei
Summary: Designable anodic aluminum oxide templates with controllable in-plane and out-of-plane shapes, sizes, spatial configurations, and pore combinations were fabricated in this study. These templates provide a useful platform for achieving well-defined nanostructuring, demonstrating enhanced performance.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Hewei Zhang, Ping Zhou, Abdalghani Daaoub, Sara Sangtarash, Shiqiang Zhao, Zixian Yang, Yu Zhou, Yu-Ling Zou, Silvio Decurtins, Robert Haener, Yang Yang, Hatef Sadeghi, Shi-Xia Liu, Wenjing Hong
Summary: Nitrogen doping of graphene leads to graphene heterojunctions with a tunable bandgap, suitable for various applications. In this work, atomically well-defined N-doped graphene heterojunctions were fabricated and their electronic properties were investigated. It was found that different doping numbers and positions of nitrogen atoms affected the conductance of the heterojunctions significantly. Furthermore, the insertion of nitrogen atoms into the conjugation framework of graphene stabilized the molecular orbitals and altered their relative positions to the Fermi level of the electrodes.
Article
Chemistry, Physical
Run Li, Qinyuan Jiang, Fei Wang, Xiaofei Shi, Fengxiang Chen, Ya Huang, Baoshun Wang, Wenshuo Zhang, Xueke Wu, Fei Wei, Rufan Zhang
Summary: A fast and simple method using tar nanodroplets from smoke allows for the optical observation of individual suspended CNTs and CNT networks under conventional optical microscopes. This visualization approach is environmentally friendly, cost-effective, and easy to operate.
Article
Engineering, Environmental
Xin Wu, Shouwei Zuo, Mei Qiu, Yang Li, Yongfan Zhang, Pengfei An, Jing Zhang, Huabin Zhang, Jian Zhang
Summary: This study successfully locates isolated Co atoms on the surface of TiO2 nanosheets, providing efficient catalytic sites for photocatalytic hydrogen evolution. X-ray absorption fine structure measurements confirm that the Co atoms are successfully dispersed on the TiO2 surface via grafting. Experimental and theoretical results demonstrate that the isolated Co atoms can accelerate electron transfer and hydrogen evolution reactions through effective Co-O electronic coupling.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Boyang Li, Jian Fang, Dan Xu, Hong Zhao, Hanghang Zhu, Fengwei Zhang, Zhengping Dong
Summary: This study successfully synthesized highly dispersed Co-cluster-decorated N-doped carbon nanotubes for efficient dehydrogenation of alcohols to aldehydes, followed by transformation to carboxylic acids via a Cannizzaro-type pathway. The presence of metallic Co clusters with almost atomic dispersion and the enhanced catalytic activity of Co clusters on N-doped carbon supports were confirmed. The work presents an effective and simple approach for the design and synthesis of small Co-clusters catalysts for the transformation of alcohols to carboxylic acids under mild reaction conditions.
Article
Chemistry, Multidisciplinary
Min Zhang, Muhammad Arif, Yuxiang Hua, Bo Qiu, Yue Mao, Xiaoheng Liu
Summary: This study successfully synthesized α-MnO2 nanocubes and α-MnO2@MnIn2S4 hybrid photocatalysts, with MnIn2S4 nanosheets growing on α-MnO2 nanocubes to form a hierarchical structure. XRD and XPS confirmed the coexistence of the two substances in the hybrid system. The composite catalyst showed improved catalytic activity in reducing 4-nitroaniline and Cr(vi) compared to individual components, and the Z-scheme electron transport mechanism enhanced the performance in organic synthesis and environmental remediation.
NANOSCALE ADVANCES
(2021)
Article
Nanoscience & Nanotechnology
Vladimir Sayevich, Zachary L. Robinson, Younghee Kim, Oleg V. Kozlov, Heeyoung Jung, Tom Nakotte, Young-Shin Park, Victor I. Klimov
Summary: This study presents high-quality near-infrared emitters based on CdSe/CdS heterostructures, which are converted from normally visible emitters to highly efficient near-infrared fluorophores by incorporating an HgS interlayer. The structures synthesized in this study exhibit highly efficient photoluminescence with atomic-level precision in defining the thickness of the HgS interlayer, resulting in 'quantized' jumps of the photoluminescence spectrum. Furthermore, the emission from these colloidal quantum dots is virtually blinking free and shows nearly perfect single-photon purity, making them promising for various applications.
NATURE NANOTECHNOLOGY
(2021)
Article
Chemistry, Physical
Anthony R. Poggioli, David T. Limmer
Summary: While hexagonal boron nitride and graphite have similar crystallography and equilibrium structuring of water, their nanoscopic channels exhibit an order-of-magnitude difference in fluid slip due to the distinct chemistries of the two materials.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Ligang Ma, Junlin Li, Zhiwei Zhang, Hao Yang, Xueqin Mu, Xiangyao Gu, Huihui Jin, Ding Chen, Senlin Yan, Suli Liu, Shichun Mu
Summary: The interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is crucial for enhancing the intrinsic activity of catalysts towards the oxygen reduction reaction (ORR). By incorporating atomically dispersed dual Fe centers into N-doped carbon nanotubes, a high intrinsic activity ORR catalyst was developed with exceptional activity surpassing state-of-the-art Pt/C. This catalyst not only exhibits superior kinetic properties but also enables primary Zn-air batteries to achieve high power densities and sufficient cycling stability.
Article
Nanoscience & Nanotechnology
Ayvaz Davletkhanov, Aram Mkrtchyan, Alexey Bunkov, Dmitry Chermoshentsev, Mikhail Shashkov, Daniil Ilatovskii, Dmitry Krasnikov, Albert Nasibulin, Yuriy Gladush
Summary: This letter investigates the optical transmission properties of waveguides covered with thin films. It is found that under certain conditions, a reduction in material loss can lead to an increase in propagation losses in the waveguide. Experimental and numerical simulation results suggest that this nontrivial behavior is due to mode reshaping caused by changes in the absorption coefficient of the covering film. The findings offer new perspectives for engineering complex reconfigurable nonlinear optical responses and transmittance dependences of nanomaterial covered waveguides.
Article
Nanoscience & Nanotechnology
Yoshitaka Shingaya, Amir Zulkefli, Takuya Iwasaki, Ryoma Hayakawa, Shu Nakaharai, Kenji Watanabe, Takashi Taniguchi, Yutaka Wakayama
Summary: This paper presents a dual-gate anti-ambipolar transistor (AAT) with a two-dimensional ReS2 and WSe2 heterojunction, where the characteristic ?-shaped transfer curves controlled by the top-gate voltage effectively control the bottom-gate voltage. This feature is applied to logic operations, allowing the AAT to perform all two-input logic operations under optimized input voltages and achieve switching between AND and OR logic operations induced by the drain voltage.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Physics, Applied
Xingzhou Chen, Zheng Sun, Min Zhang, Ming Li, Zhigao Hu, Kenji Watanabe, Takashi Taniguchi, David Snoke, Zhe-Yu Shi, Jian Wu
Summary: We have designed and fabricated a vertical structure using a distributed Bragg reflector and dielectric material layer to enhance optical absorption in a stack of monolayer WS2 and MoS2. Our research shows a tenfold increase in absorption over a 100 nm spectral range, with the potential to achieve over 50% absorption by tuning the spacer layer thickness. Our theoretical model explains the dependence of absorption coefficient on spacer thickness as a solution of a non-Hermitian Schrodinger equation. These findings contribute to the development of broadband optical devices utilizing two-dimensional excitonic materials.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Yihang Zeng, Zhengchao Xia, Roei Dery, Kenji Watanabe, Takashi Taniguchi, Jie Shan, Kin Fai Mak
Summary: In a heterostructure composed of WS2/bilayer WSe2/WS2 multilayers, it was discovered that strongly correlated bosons can be trapped in a triangular lattice. Correlated insulating states were observed when the electron filling factor of the two lattices reached 1/3, 2/3, 4/3, and 5/3. These states can be explained as exciton density waves in a Bose-Fermi mixture of excitons and holes. The strong repulsive interactions between the constituents led to the formation of robust generalized Wigner crystals, which restricted the exciton fluid to channels that spontaneously broke the translational symmetry of the lattice. These results demonstrate that Coulomb-coupled lattices are a fertile ground for studying correlated many-boson phenomena.
Article
Chemistry, Multidisciplinary
Matthew S. G. Feuer, Alejandro R. -P. Montblanch, Mohammed Y. Sayyad, Carola M. Purser, Ying Qin, Evgeny M. Alexeev, Alisson R. Cadore, Barbara L. T. Rosa, James Kerfoot, Elaheh Mostaani, Radoslaw Kaleba, Pranvera Kolari, Jan Kopaczek, Kenji Watanabe, Takashi Taniguchi, Andrea C. Ferrari, Dhiren M. Kara, Sefaattin Tongay, Mete Atature
Summary: Janus transition-metal dichalcogenide monolayers are artificial materials with unique properties, such as long-lived, dipolar excitons and direct-band gap optical transitions. In this study, the specific excitonic origin of Janus WSe S monolayers with narrow optical line widths is identified. The integration of Janus monolayers into vertical heterostructures allows for doping control and the development of optoelectronic devices. These findings have important implications for nanoscale sensing and the advancement of Janus-based technology.
Article
Chemistry, Multidisciplinary
Jinpeng Tian, Qinqin Wang, Xudan Huang, Jian Tang, Yanbang Chu, Shuopei Wang, Cheng Shen, Yancong Zhao, Na Li, Jieying Liu, Yiru Ji, Biying Huang, Yalin Peng, Rong Yang, Wei Yang, Kenji Watanabe, Takashi Taniguchi, Xuedong Bai, Dongxia Shi, Luojun Du, Guangyu Zhang
Summary: This study presents a self-encapsulated heterostructure undercut technique for fabricating sub-10 nm channel length MoS2 FETs. The 9 nm channel MoS2 FETs fabricated using this technique exhibit superior performances and excellent homogeneity.
Article
Chemistry, Physical
Jian-Xiang Qiu, Christian Tzschaschel, Junyeong Ahn, Anyuan Gao, Houchen Li, Xin-Yue Zhang, Barun Ghosh, Chaowei Hu, Yu-Xuan Wang, Yu-Fei Liu, Damien Berube, Thao Dinh, Zhenhao Gong, Shang-Wei Lien, Sheng-Chin Ho, Bahadur Singh, Kenji Watanabe, Takashi Taniguchi, David C. Bell, Hai-Zhou Lu, Arun Bansil, Hsin Lin, Tay-Rong Chang, Brian B. Zhou, Qiong Ma, Ashvin Vishwanath, Ni Ni, Su-Yang Xu
Summary: Using circularly polarized light, researchers have observed helicity-dependent optical control of fully compensated antiferromagnetic order in a topological axion insulator called MnBi2Te4. This optical control and circular dichroism are based on the optical axion electrodynamics and can potentially be used to control PT-symmetric antiferromagnets and create dissipationless circuits using topological edge states.
Article
Multidisciplinary Sciences
Pingfan Gu, Cong Wang, Dan Su, Zehao Dong, Qiuyuan Wang, Zheng Han, Kenji Watanabe, Takashi Taniguchi, Wei Ji, Young Sun, Yu Ye
Summary: The authors demonstrate a magnetoelectric effect in a van der Waals antiferromagnetic CrOCl material, which allows for multi-state data storage. This material shows promise for new data storage technologies with low power consumption, functionality, and high energy efficiency.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Di Huang, Kevin Sampson, Yue Ni, Zhida Liu, Danfu Liang, Kenji Watanabe, Takashi Taniguchi, Hebin Li, Eric Martin, Jesper Levinsen, Meera M. Parish, Emanuel Tutuc, Dmitry K. Efimkin, Xiaoqin Li
Summary: When mobile impurities are introduced and coupled to a Fermi sea, new quasiparticles called Fermi polarons are formed. There are two regimes of the Fermi polaron problem: attractive polarons (AP) connected to pairing phenomena, and repulsive polarons (RP) responsible for ferromagnetism. In this study, we investigate Fermi polarons in a doped MoSe2 monolayer and find agreement with polaron theory for attractive polarons. The dynamics of Fermi polarons are important for understanding pairing and magnetic instabilities in various physical systems.
Article
Nanoscience & Nanotechnology
Dong Hoon Shin, Duk Hyun Lee, Sang-Jun Choi, Seonyeong Kim, Hakseong Kim, Kenji Watanabe, Takashi Taniguchi, Eleanor E. B. Campbell, Sang Wook Lee, Suyong Jung
Summary: Weak interlayer couplings at 2D van der Waals interfaces fundamentally distinguish out-of-plane charge flow, the information carrier in vdW-assembled vertical electronic and optical devices, from the in-plane band transport processes. The out-of-plane charge transport behavior in 2D van der Waals semiconducting transition metal dichalcogenides (SCTMD) is studied and it is found that Fowler-Nordheim tunneling becomes the dominant quantum transport process in ultrathin SCTMDs, down to monolayers, in the high electric field regime, especially at low temperatures. The sequential layer-by-layer FN tunneling is observed to dominate the charge flow in few-layer SCTMDs, providing insight into the Fermi level positions and layer numbers of the SCTMD films.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yueh-Chun Wu, Takashi Taniguchi, Kenji Watanabe, Jun Yan
Summary: Monolayer transition metal dichalcogenide semiconductors are promising valleytronic materials, and the valley polarized holes are particularly interesting due to their long valley lifetime preserved by the large spin-orbit splitting and spin-valley locking.
Article
Chemistry, Multidisciplinary
Priya Tiwari, Divya Sahani, Atasi Chakraborty, Kamal Das, Kenji Watanabe, Takashi Taniguchi, Amit Agarwal, Aveek Bid
Summary: In this study, the experimental evidence of the time-reversal symmetric Hall effect in high-mobility graphene-WSe2 heterostructures is provided. This dissipative Hall effect is linear and its sign depends on the charge carriers. It persists up to room temperature and can be tuned using an external electric field. The strain induced by lattice mismatch or alignment angle inhomogeneity breaks the inversion symmetry and produces anisotropic bands in graphene, leading to the appearance of a time-reversal symmetric Hall effect.
Article
Multidisciplinary Sciences
Dacen Waters, Ellis Thompson, Esmeralda Arreguin-Martinez, Manato Fujimoto, Yafei Ren, Kenji Watanabe, Takashi Taniguchi, Ting Cao, Di Xiao, Matthew Yankowitz
Summary: Moire patterns formed by stacking twisted atomically thin van der Waals crystals can modify the electronic properties of bulk graphitic thin films in a dual-gated device. At zero and small magnetic fields, transport is mediated by gate-tuneable moire and graphite surface states, as well as coexisting semimetallic bulk states. At high field, the moire potential hybridizes with the graphitic bulk states, creating a single quasi-two-dimensional hybrid structure. This study establishes twisted graphene-graphite as a new class of mixed-dimensional moire materials.
Article
Physics, Multidisciplinary
Gelareh Farahi, Cheng-Li Chiu, Xiaomeng Liu, Zlatko Papic, Kenji Watanabe, Takashi Taniguchi, Michael P. P. Zaletel, Ali Yazdani
Summary: We demonstrate a non-invasive spectroscopic technique with a scanning tunnelling microscope, which allows us to investigate the broken-symmetry states and excitation spectrum of the partially filled zeroth Landau level in graphene. Our experimental approach quantifies the interacting phase diagram of the zeroth Landau level and provides insights into the repulsive interactions underlying the fractional quantum states.
Article
Chemistry, Multidisciplinary
Karolina Ewa Polczynska, Simon Le Denmat, Takashi Taniguchi, Kenji Watanabe, Marek Potemski, Piotr Kossacki, Wojciech Pacuski, Jacek Kasprzak
Summary: Using four-wave mixing microscopy, the coherent response and ultrafast dynamics of excitons and trions in MoSe2 monolayers grown by molecular beam epitaxy on thin films of hexagonal boron nitride are measured. The inhomogeneous and homogeneous broadenings in the transition spectral lineshape are evaluated. The impact of phonons on the homogeneous dephasing is inferred through the temperature dependence of the dephasing. Four-wave mixing mapping combined with atomic force microscopy reveals spatial correlations between exciton oscillator strength, inhomogeneous broadening, and the sample morphology. The quality of the coherent optical response of epitaxially grown transition metal dichalcogenides is now comparable to mechanically exfoliated samples, enabling the coherent nonlinear spectroscopy of innovative materials such as magnetic layers or Janus semiconductors.
Article
Nanoscience & Nanotechnology
Kai Liu, Jian Zheng, Yating Sha, Bosai Lyu, Fengping Li, Youngju Park, Yulu Ren, Kenji Watanabe, Takashi Taniguchi, Jinfeng Jia, Weidong Luo, Zhiwen Shi, Jeil Jung, Guorui Chen
Summary: Interactions among charge carriers in graphene can lead to the spontaneous breaking of multiple degeneracies. In this study, the stacking orders of tetralayer graphene devices were determined using near-field infrared imaging. Through quantum transport measurements, a range of spontaneous broken-symmetry states and their transitions were observed, which could be finely tuned by carrier density and electric displacement field. These findings highlight the potential of multilayer graphene as a platform for investigating broken symmetries.
NATURE NANOTECHNOLOGY
(2023)
