Article
Engineering, Electrical & Electronic
Yunfeng Chen, Yang Wang, Zhen Wang, Yue Gu, Yan Ye, Xuliang Chai, Jiafu Ye, Yan Chen, Runzhang Xie, Yi Zhou, Zhigao Hu, Qing Li, Lili Zhang, Fang Wang, Peng Wang, Jinshui Miao, Jianlu Wang, Xiaoshuang Chen, Wei Lu, Peng Zhou, Weida Hu
Summary: Band-engineered van der Waals heterostructures are able to construct high room-temperature detectivity detectors for visible light and blackbody infrared light by blocking dark current without suppressing photocurrent. Utilizing two-dimensional materials with self-passivated surfaces and tunable band structures, unipolar barriers can be designed to avoid lattice mismatch and interface defects, achieving low dark current and high detectivity in photodetectors.
NATURE ELECTRONICS
(2021)
Review
Chemistry, Multidisciplinary
Xiangdong Guo, Wei Lyu, Tinghan Chen, Yang Luo, Chenchen Wu, Bei Yang, Zhipei Sun, F. Javier Garcia de Abajo, Xiaoxia Yang, Qing Dai
Summary: 2D monolayers can be vertically stacked in van der Waals heterostructures to support a wide range of confined polaritons. This offers advantages in terms of controlling the constituent layers, stacking sequence, and twist angles. These heterostructures have extended the performance and functions of polaritons, and potential applications include nanophotonic integrated circuits.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Wenxiang Wang, Jiyou Jin, Yanrong Wang, Zheng Wei, Yushi Xu, Zhisheng Peng, Hui Liu, Yu Wang, Jiawang You, Julienne Impundu, Qiang Zheng, Yong Jun Li, Lianfeng Sun
Summary: A floating-gate memory based on van der Waals heterostructure is utilized, demonstrating a large storage window ratio (>75.5%), an extremely high on/off ratio (10^7), and an ultrafast electrical writing/erasing speed (40 ns). These enhanced performance characteristics enable excellent multilevel data storage, robust retention, and endurance performance. Stable optical erasing operations can also be achieved by illuminating the device with a laser pulse, showcasing outstanding optoelectronic storage performance (optical erasing speed >2.3 ms). The nonvolatile and high-speed characteristics of these devices hold significant potential for the integration of high-performance nonvolatile memory.
Article
Chemistry, Physical
Mengmeng Jia, Jinran Yu, Yudong Liu, Pengwen Guo, Ying Lei, Wei Wang, Aifang Yu, Yaxing Zhu, Qijun Sun, Junyi Zhai, Zhong Lin Wang
Summary: This study introduces a new multibit tribotronic nonvolatile memory based on a graphene/hexagonal boron nitride/molybdenum disulfide van der Waals heterostructure and triboelectric nanogenerator, showing promising performance in modulation of programming/erasing states through external mechanical actions, long retention time, stable switching behavior, and multilevel data storage capability. Additionally, a memory inverter circuit utilizing the triboelectric potential as input signals demonstrates the potential of tribotronic devices for various applications in human-robot interactions, self-powered wearable devices, and intelligent instrumentation.
Article
Nanoscience & Nanotechnology
Xin He, Chenhui Zhang, Dongxing Zheng, Peng Li, John Q. Xiao, Xixiang Zhang
Summary: With the recent advancements in two-dimensional ferromagnets, it is now feasible to develop high-quality all-2D spintronic devices. In this study, nonlocal spin valves were successfully fabricated using Fe3GeTe2 as the spin source and detector and multilayer graphene as the spin transport channel. The spin transport signal strongly depended on temperature and vanished below the Curie temperature of the Fe3GeTe2 flakes. Our results suggest potential applications of van der Waals heterostructures in spintronic devices.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Review
Chemistry, Multidisciplinary
Hui-Lei Hou, Cosimo Anichini, Paolo Samori, Alejandro Criado, Maurizio Prato
Summary: In the past 15 years, 2D materials have revolutionized materials science and become powerful components for high-performance chemical sensors. By forming van der Waals heterostructures (VDWHs), the individual drawbacks of 2D materials can be overcome, leading to superior sensitivities, selectivity, and stability. This review discusses the latest developments in chemical sensors based on VDWHs of 2D materials, including sensing mechanisms and future directions with potential impact in environmental sciences and biomedical applications.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Review
Chemistry, Multidisciplinary
Sofie Cambre, Ming Liu, Dmitry Levshov, Keigo Otsuka, Shigeo Maruyama, Rong Xiang
Summary: 1D van der Waals heterostructures based on carbon nanotube templates offer exciting possibilities for creating new optical and electronic properties. By engineering the characteristics of these heterostructures through controlling their diameter and chiral structure, they can be integrated into a wide range of applications with custom-built properties.
Review
Materials Science, Multidisciplinary
Lixin Liu, Tianyou Zhai
Summary: The article reviews the latest research activities on wafer-scale vdWHs and their applications, outlining preparation strategies and applications to showcase their potential in electronic, optoelectronic, and flexible devices fields.
Article
Chemistry, Multidisciplinary
Xuan Ji, Zongqi Bai, Fang Luo, Mengjian Zhu, Chucai Guo, Zhihong Zhu, Shiqiao Qin
Summary: The research team successfully fabricated MoTe2-MoS2 van der Waals heterostructure photodetectors with great performance, operating without bias voltage, high photocurrent on/off ratio, and high photoresponsivity.
Article
Materials Science, Multidisciplinary
Jiachao Zhou, Lingfei Li, Akeel Qadir, Hanxi Li, Jianhang Lv, Khurram Shehzad, Xinyi Xu, Lixiang Liu, Feng Tian, Wei Liu, Li Chen, Li Yu, Xin Su, Srikrishna Chanakya Bodepudi, Huan Hu, Yuda Zhao, Bin Yu, Xiaomu Wang, Yang Xu
Summary: This study reports on a photodetector based on fully 2D van der Waals heterostructures. It stores photo-charges generated in the absorption layer and utilizes a stacked transistor for nondestructive readout, enabling weak signal detection and imaging with high resolution and low noise. The device achieves broadband detection from visible to mid-IR range at room temperature and low operation voltage, making it a promising candidate for future photodetectors.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Muhammad A. K. Purbayanto, Madhurya Chandel, Magdalena Birowska, Andreas Rosenkranz, Agnieszka M. Jastrzebska
Summary: This article discusses the fundamental basis and recent findings in vertical vdW heterostructures composed of MXenes as a primary component and other 2D materials as secondary components. MXenes, with their rich surface chemistry and intriguing optical properties, offer a unique platform for optoelectronics applications. Coupling MXenes with other 2D materials in vdW heterostructures can provide new opportunities for exploring novel physical phenomena in quantum-confined nanostructures and devices.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Carla Boix-Constant, Victor Garcia-Lopez, Efren Navarro-Moratalla, Miguel Clemente-Leon, Jose Luis Zafra, Juan Casado, Francisco Guinea, Samuel Manas-Valero, Eugenio Coronado
Summary: Van der Waals heterostructures offer the possibility of engineering new materials with unique functionalities by assembling different materials in layered structures. In this study, a molecular building block capable of producing strain, known as spin-crossover, is introduced to expand the family of van der Waals heterostructures. The electronic and optical properties of 2D materials can be switched by the strain accompanying the spin transition in smart van der Waals heterostructures. These molecular/inorganic heterostructures have significant applications in the fields of straintronics and band engineering in low-dimensional materials.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Hao Wang, Lihong Bao, Roger Guzman, Kang Wu, Aiwei Wang, Li Liu, Liangmei Wu, Jiancui Chen, Qing Huan, Wu Zhou, Sokrates T. Pantelides, Hong-Jun Gao
Summary: The development of electrically ultrafast-programmable semiconductor homojunctions can lead to transformative multifunctional electronic devices. Here, 2D, multi-functional, lateral homojunctions made of van der Waals heterostructures with a semi-floating-gate configuration on a p(++) Si substrate are introduced. These homojunctions can be electrostatically programmed in nanoseconds, and have rectification ratio up to & AP;10(5), enabling them to function as logic rectifiers, memories, and multi-valued logic inverters. The devices are also compatible with Si technology.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Andrey Yu Klokov, Nikolay Yu Frolov, Andrey Sharkov, Sergey N. Nikolaev, Maxim A. Chernopitssky, Semen Chentsov, Mikhail Pugachev, Aliaksandr Duleba, Alexey Shupletsov, Vladimir S. Krivobok, Aleksandr Yu Kuntsevich
Summary: This study explores the mechanical properties of layered crystals in the few layer limit using picosecond ultrasonic technique. By measuring the temporal variation of the reflection coefficient of an Al film covering heterostructures, the mechanical parameters and rigidity of the interfaces can be evaluated. The results demonstrate the potential of van der Waals heterostructures for nanoacoustical applications.
Article
Chemistry, Multidisciplinary
Maria G. Burdanova, Ming Liu, Michael Staniforth, Yongjia Zheng, Rong Xiang, Shohei Chiashi, Anton Anisimov, Esko Kauppinen, Shigeo Maruyama, James Lloyd-Hughes
Summary: Strong intertube excitonic coupling is demonstrated in 1D van der Waals heterostructures through the interaction of dipole-dipole Coulomb interactions and light-matter interactions. This leads to the creation of intertube biexcitons on short timescales and intertube excitons on longer timescales, which opens up new possibilities for multi-functional applications of these new nanoscale coaxial cables.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Dmitry Lebedev, Jonathan Tyler Gish, Ethan Skyler Garvey, Teodor Kosev Stanev, Junhwan Choi, Leonidas Georgopoulos, Thomas Wei Song, Hong Youl Park, Kenji Watanabe, Takashi Taniguchi, Nathaniel Patrick Stern, Vinod Kumar Sangwan, Mark Christopher Hersam
Summary: 2D magnetic materials have promising applications in quantum and spintronic devices. 2D antiferromagnetic materials are of interest due to their insensitivity to external magnetic fields and faster switching speeds compared to 2D ferromagnets. However, their lack of macroscopic magnetization hampers the detection and control of antiferromagnetic order, emphasizing the need for magneto-electrical measurements.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Dohun Kim, Byungmin Kang, Yong-Bin Choi, Kenji Watanabe, Takashi Taniguchi, Gil-Ho Lee, Gil Young Cho, Youngwook Kim
Summary: We introduce a novel two-dimensional electronic system called twisted bilayer graphene with a large twist angle, which exhibits ultrastrong interlayer interactions and is ideal for realizing interlayer-coherent excitonic condensates. By fully exploiting the sub-nanometer atomic separation and geometrically suppressed interlayer electron tunneling, we demonstrate the appearance of a sequence of odd-integer quantum Hall states with interlayer coherence at the second Landau level (N = 1). These states have energy gaps of order 1 K, several orders of magnitude greater than those in GaAs. Experimental observations of various quantum Hall phase transitions largely support our phenomenological model calculations. Therefore, we establish the excellent platform of a large twist angle system for high-temperature excitonic condensation.
Article
Nanoscience & Nanotechnology
Ryoichi Kato, Haruki Uchiyama, Tomonori Nishimura, Keiji Ueno, Takashi Taniguchi, Kenji Watanabe, Edward Chen, Kosuke Nagashio
Summary: In this study, high-performance p-type FETs were achieved by selectively applying surface charge-transfer doping from WOx to the access region of WS2 and WSe2. The p-type conversion of intrinsically n-type trilayer WSe2 FET was successfully achieved by reducing the Schottky barrier width and injecting holes into the valence band. However, trilayer WS2 did not show clear p-type conversion due to its lower valence band maximum compared to trilayer WSe2. Using h-BN as a TG insulator, a high-performance p-type WSe2 FET with negligible hysteresis was achieved.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Kento Sasaki, Yuki Nakamura, Hao Gu, Moeta Tsukamoto, Shu Nakaharai, Takuya Iwasaki, Kenji Watanabe, Takashi Taniguchi, Shinichi Ogawa, Yukinori Morita, Kensuke Kobayashi
Summary: Placing a sensor close to the target at the nano-level is a central challenge in quantum sensing. We demonstrate magnetic field imaging with a boron vacancy (V-B(-)) defects array in hexagonal boron nitride with a few 10 nm thickness. The sensor array allows us to visualize the magnetic field induced by the current in the straight micro wire with a high spatial resolution. Each sensor exhibits a practical sensitivity of 73.6 mu T/Hz(0.5), suitable for quantum materials research. Our technique of arranging V-B(-) quantum sensors periodically and tightly on measurement targets will maximize their potential.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Martin Endres, Artem Kononov, Hasitha Suriya Arachchige, Jiaqiang Yan, David Mandrus, Kenji Watanabe, Takashi Taniguchi, Christian Schoenenberger
Summary: In this study, we measured a 4N-periodic switching current through an asymmetric SQUID formed by the higher-order topological insulator WTe2. We found that a high asymmetry in critical current and negligible loop inductance alone were not sufficient to reliably measure the current-phase relation. Instead, we discovered that our measurement was heavily influenced by additional inductances originating from the self-formed PdTex inside the junction. We developed a method to numerically recover the current-phase relation and found that the 1.5 μm long junction was best described in the short ballistic limit. Our results highlight the complexity of subtle inductance effects that can lead to misleading topological signatures in transport measurements.
Article
Multidisciplinary Sciences
Wenjin Zhao, Bowen Shen, Zui Tao, Zhongdong Han, Kaifei Kang, Kenji Watanabe, Takashi Taniguchi, Kin Fai Mak, Jie Shan
Summary: Scientists have realized synthetic Kondo lattice in AB-stacked MoTe2/WSe2 moire bilayers, observing heavy fermions and demonstrating gate-tunable Kondo temperatures. This study opens the possibility of accessing the phase diagram of the Kondo lattice using semiconductor moire materials.
Article
Nanoscience & Nanotechnology
Kaifei Kang, Wenjin Zhao, Yihang Zeng, Kenji Watanabe, Takashi Taniguchi, Jie Shan, Kin Fai Mak
Summary: We have achieved the pulsed control of the superlattice effect in two-dimensional materials through the ferroelectric effect, switching between the correlated and superlattice insulating states, and observing the nonlinear anomalous Hall effect. This study demonstrates the potential for creating new functional superlattice materials by incorporating intrinsic symmetry-breaking orders.
NATURE NANOTECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Richen Xiong, Jacob H. Nie, Samuel L. Brantly, Patrick Hays, Renee Sailus, Kenji Watanabe, Takashi Taniguchi, Sefaattin Tongay, Chenhao Jin
Summary: We observe a bosonic correlated insulator composed of excitons in tungsten diselenide/tungsten disulfide (WSe2/WS2) moire superlattices. The insulator transitions continuously into an electron correlated insulator with varying charge density, suggesting a mixed correlated insulating state between the two limits.
Article
Materials Science, Multidisciplinary
Nikodem Sokolowski, Swaroop Palai, Mateusz Dyksik, Katarzyna Posmyk, Michal Baranowski, Alessandro Surrente, Duncan Maude, Felix Carrascoso, Onur Cakiroglu, Estrella Sanchez, Alina Schubert, Carmen Munuera, Takashi Taniguchi, Kenji Watanabe, Joakim Hagel, Samuel Brem, Andres Castellanos-Gomez, Ermin Malic, Paulina Plochocka
Summary: In this study, the influence of twist angle on momentum-indirect excitons (IXs) in a MoSe2/MoS2 heterostructure was investigated using spectroscopy and many-particle theory. It was found that increasing the twist angle led to a significant blue shift of the excitons due to dehybridization. Furthermore, for small twist angle heterostructures, two IX states were observed through photoluminescence measurements, which were attributed to transitions from different moire minibands. This research contributes to a better understanding of the hybridization of momentum-dark IX states influenced by the moire pattern, which is important for applications in moire-tronics and quantum technologies.
Article
Chemistry, Multidisciplinary
Xintong Li, Peng Zhou, Xuan Hu, Ethan Rivers, Kenji Watanabe, Takashi Taniguchi, Deji Akinwande, Joseph S. Friedman, Jean Anne C. Incorvia
Summary: Ambipolar dual-gate transistors based on low-dimensional materials enable reconfigurable logic circuits with suppressed off-state current. This article presents high-performance ambipolar dual-gate transistors based on tungsten diselenide (WSe2), which exhibit high on-off ratio, low off-state current, negligible hysteresis, and ideal subthreshold swing. Cascadable logic gates with minimal static power consumption are demonstrated using these transistors. The study also investigates the behavior of both control gate and polarity gate and analyzes the noise margin and speed performance of the circuits built by dual-gate devices. This work advances the field of ambipolar dual-gate transistors and showcases their potential for low-power, high-speed, and more flexible logic circuits.
Article
Chemistry, Multidisciplinary
Hakon Rost, Simon P. Cooil, Anna Cecilie Asland, Jinbang Hu, Ayaz Ali, Takashi Taniguchi, Kenji Watanabe, Branson D. Belle, Bodil Holst, Jerzy T. Sadowski, Federico Mazzola, Justin W. Wells
Summary: Understanding the collective behavior of quasiparticles in solid-state systems is crucial for nonvolatile electronics, allowing control of many-body effects and their applications. Hexagonal boron nitride (hBN) is a wide-energy-bandgap semiconductor with potential for low-dimensional device heterostructures. Despite its inertness, few-layer hBN shows a significant increase in electron mass, affecting the lifetime of pi-band states. The enhancement is phonon-mediated and has important implications for hBN-based devices.
Article
Chemistry, Physical
Lujun Wang, Sotirios Papadopoulos, Fadil Iyikanat, Jian Zhang, Jing Huang, Takashi Taniguchi, Kenji Watanabe, Michel Calame, Mickael L. Perrin, F. Javier Garcia de Abajo, Lukas Novotny
Summary: The authors demonstrate exciton-assisted resonant electron tunnelling in van der Waals heterostructure tunnel junctions. They reveal tunnelling mechanisms involving indirect or direct excitons and optical emission driven by inelastic electron tunnelling. The study highlights the importance of materials with well-defined interfaces and the potential for van der Waals material-based optoelectronic devices.
Article
Multidisciplinary Sciences
Xin Cong, Parisa Ali Mohammadi, Mingyang Zheng, Kenji Watanabe, Takashi Taniguchi, Daniel Rhodes, Xiao-Xiao Zhang
Summary: The study investigates the characteristics of Fermi sea screening on dark excitons in monolayer WSe2 and its correlation with carrier density. The results indicate that the photoluminescence of dark excitons shows distinct p-doping dependence when the carrier density reaches a critical level.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Lei Ren, Cedric Robert, Hanan Dery, Minhao He, Pengke Li, Dinh Van Tuan, Pierre Renucci, Delphine Lagarde, Takashi Taniguchi, Kenji Watanabe, Xiaodong Xu, Xavier Marie
Summary: We investigated charge tunable devices based on WSe2 and WS2 monolayers encapsulated in hexagonal boron nitride. We observed a weaker-intensity optical transition in photoluminescence measurements when the monolayers were electrostatically doped with electrons. Through a detailed characterization of this photoluminescence line, we identified it as an impurity-assisted radiative recombination of the intervalley negatively charged exciton (triplet trion). Our measurements also revealed the spin-orbit splitting energy difference between the emitted photons from the two possible recombination processes of the same triplet trion.
Article
Chemistry, Multidisciplinary
Tien Dat Ngo, Tuyen Huynh, Inyong Moon, Takashi Taniguchi, Kenji Watanabe, Min Sup Choi, Won Jong Yoo
Summary: This study presents a novel approach to overcome the challenges faced by 2D materials in CMOS technology, specifically in the production of high-performance p-type field effect transistors (p-FETs). By fabricating lateral p+-p-p+ junction WSe2 FETs with self-aligned TG stacks and utilizing selective oxygen plasma-doping, the researchers achieve exceptional electrostatic controllability and low power consumption in PMOS inverters.