检索结果-内蒙古大学图书馆

Design of Mixed-Dimensional QDs/MoS2/TiO2 Heterostructured Resistive Random-Access Memory with Interfacial Analog Switching Characteristics for Potential Neuromorphic Computing

引用

ACS Applied Electronic materials 2024年第3期6卷 1581-1589页

作者： Tang, Shin-Yi Shih, Yu-Chuan Shen, Ying-Chun Cyu, Ruei-Hong Chen, Chieh-Ting Yang, Tzu-Yi Chaudhary, Mayur Peng, Yu-Ren Kuo, Yao-Ren Miao, Wen-Chien Yu, Yi-Jen Lee, Ling Kuo, Hao-Chung Chueh, Yu-Lun Department of Materials Science and Engineering National Tsing Hua University Hsinchu30013 Taiwan College of Semiconductor Research National Tsing Hua University Hsinchu30013 Taiwan Semiconductor Research Center Hon Hai Research Institute Taipei11492 Taiwan Ph. D. Program in Prospective Functional Materials Industry National Tsing Hua University Hsinchu30013 Taiwan Department of Electrophysics College of Science National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Instrument Center National Tsing Hua University Hsinchu30013 Taiwan Department of Photonics Institute of Electro-Optical Engineering National Yang-Ming Chiao Tung University Hsinchu30010 Taiwan Department of Physics National Sun Yat-Sen University Kaohsiung80424 Taiwan Department of Materials Science and Engineering Korea University Seoul02841 Korea Republic of

Resistive random-access memory (RRAM) is one of the most promising candidates for next-generation nanoscale nonvolatile memory devices and neuromorphic computing applications. In this study, we developed a novel mixed-dimensional design for RRAM devices, incorporating zero-dimensional quantum dots (QDs), two-dimensional MoS2, and a TiO2 switching layer to achieve prominent interfacial switching behaviors. Compared with typical filamentary RRAM devices, the proposed heterostructure featured a light-sensitive QDs/MoS2 layer that allowed for bias-controllable resistive changes during the set and reset processes without abrupt switching. This was endowed by effective electron-hole pair separations upon excitation and the generation of a thin molybdenum oxide (MoOx) layer due to the accumulation of oxygen ions at the interface between MoS2 and TiO2. The ITO/QDs/MoS2/TiO2/Pt RRAM device exhibited an on/off ratio of 10 with improved endurance under 515 nm laser illumination and wavelength-dependent resistive switching behavior, making it useful for multilevel storage. Furthermore, the heterostructured device demonstrated synaptic characteristics with enhanced potentiation and depression nonlinearities and asymmetry factors, revealing its potential for future neuromorphic applications. © 2024 American Chemical Society.

关键词： Titanium dioxide

来源：评论

学校读者我要写书评

暂无评论

In-situ TEM-STM Observations of SWCNT Ropes/tubular Transformations

引用

MRS Online Proceedings Library 2010年第1期1204卷 1-6页

作者： F. Solá M. Lebrón-Colón P. J. Ferreira L. F. Fonseca M. A. Meador C. Marín Advanced Metallics Branch National Aeronautics and Space Administration (NASA) Glenn Research Center Structures and Materials Division Cleveland USA Polymers Branch National Aeronautics and Space Administration (NASA) Glenn Research Center Structures and Materials Division Cleveland USA Materials Science and Engineering Program University of Texas at Austin Austin USA Institute for Functional Nanomaterials and Department of Physics of the University of Puerto Rico Rio Piedras USA

Single-walled carbon nanotubes (SWCNTs) prepared by the HiPco process were purified using a modified gas phase purification technique. A TEM-STM holder was used to study the morphological changes of SWCNT ropes as a function of applied voltage. Kink formation, buckling behavior, tubular transformation and eventual breakdown of the system were observed. The tubular formation was attributed to a transformation from SWCNT ropes to multi-walled carbon nanotube (MWCNT) structures. It is likely mediated by the patching and tearing mechanism which is promoted primarily by the mobile vacancies generated due to current-induced heating and, to some extent, by electron irradiation.

关键词： transmission electron microscopy (TEM) nanostructure phase transformation

来源：评论

学校读者我要写书评

暂无评论

Graphene-based analog of single-slit electron diffraction

引用

Physical Review B 2023年第12期108卷 125420-125420页

作者： Dipanjan Saha Dacen Waters Ching-Chen Yeh Swapnil M. Mhatre Ngoc Thanh Mai Tran Heather M. Hill Kenji Watanabe Takashi Taniguchi David B. Newell Matthew Yankowitz Albert F. Rigosi Physical Measurement Laboratory National Institute of Standards and Technology (NIST) Gaithersburg Maryland 20899 USA Intelligence Community Postdoctoral Research Fellowship Program University of Washington Seattle Washington 98195 USA Department of Physics University of Washington Seattle Washington 98195 USA Department of Physics National Taiwan University Taipei 10617 Taiwan Joint Quantum Institute University of Maryland College Park Maryland 20742 USA Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan Department of Materials Science and Engineering University of Washington Seattle Washington 98195 USA

In this paper, we report on the experimental demonstration of single-slit diffraction exhibited by electrons propagating in encapsulated graphene with an effective de Broglie wavelength corresponding to their attributes as massless Dirac fermions. Nanometer-scale device designs were implemented to fabricate a single-slit followed by five detector paths. Predictive calculations were also utilized to readily understand the observations reported. These calculations required the modeling of wave propagation in ideal case scenarios of the reported device designs to more accurately describe the observed single-slit phenomenon. This experiment was performed at room temperature and 190 K, where data from the latter highlighted the exaggerated asymmetry between electrons and holes, recently ascribed to slightly different Fermi velocities near the K point. This observation and device concept may be used for building diffraction switches with versatile applicability.

关键词： Interference & diffraction of light Electrons Graphene

来源：评论

学校读者我要写书评

暂无评论

Emergence of skyrmions from rich parent phases in the molybdenum nitrides

引用

Physical Review B 2016年第6期93卷 060409(R)-060409(R)页

作者： Wei Li Chiming Jin Renchao Che Wensen Wei Langsheng Lin Lei Zhang Haifeng Du Mingliang Tian Jiadong Zang State Key Laboratory of Functional Materials for Informatics and Shanghai Center for Superconductivity Shanghai Institute of Microsystem and Information Technology and CAS-Shanghai Science Research Center Chinese Academy of Sciences Shanghai 200050 China High Magnetic Field Laboratory Chinese Academy of Science (CAS) Hefei 230031 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Jiangsu 210093 China Laboratory of Advanced Materials Department of Materials Science Collaborative Innovation Center of Chemistry for Energy Materials Fudan University Shanghai 200438 China Hefei National Laboratory for Physical Science at Microscale and Department of Physics University of Science and Technology of China Hefei 230026 China Department of Physics and Materials Science Program University of New Hampshire Durham New Hampshire 03824 USA

We report a new family of skyrmion materials originated from the antisymmetric Dzyaloshinskii-Moriya (DM) interactions. Based on the symmetric tensor technique, the molybdenum nitrides with the β-manganese structure, A2Mo3N with A=Fe, Co, Rh, are predicted to support the skyrmion phase. This predication is directly proved in doped FexCo1−xRh0.5Mo3N components by high-resolution Lorentz transmission electron imaging. Interestingly, the parent compounds Fe2Mo3N, Co2Mo3N, and Rh2Mo3N exhibit ferromagnetic, antiferromagnetic, and possible superconducting orderings, respectively. Magnetism in these parent phases is theoretically clarified by the first-principle calculations, where the corrected nature of the magnetism is revealed.

关键词： Density of states Dzyaloshinskii-Moriya interaction Magnetism Skyrmions Classical spin models Nanostructures First-principles calculations

来源：评论

学校读者我要写书评

暂无评论

Enhanced Thermoelectric Performance of Bi0.5sb1.5te3/Cu2se Composites Through the Scattering Engineering Strategy

SSRN

引用

SSRN 2023年

作者： Nakhowong, Ronariddh Chueachot, Romteera Pinitsoontorn, Supree Seetawan, Tosawat Functional Nanomaterials and Advanced Thermoelectric Materials Research Laboratory Faculty of Science Ubon Ratchathani Rajabhat University Ubon Ratchathani34000 Thailand Program of Chemistry Faculty of Science Ubon Ratchathani Rajabhat University Ubon Ratchathani34000 Thailand Khon Kaen University Khon Kaen40002 Thailand Program of Physics Faculty of Science and Technology Sakon Nakhon Rajabhat University Sakon Nakhon74000 Thailand Program of Physics Faculty of Science Ubon Ratchathani Rajabhat University Ubon Ratchathani34000 Thailand

Bi2Te3-based materials have been widely used in the field of thermoelectric generation at near room temperature. However, material utilization and conversion efficiency, including minority charge carrier excitation at high temperatures, seriously reduces thermoelectric performance with limited applications as thermoelectric power generation. Nanocomposite approaches are practical strategies to boost the thermoelectric figure of merit due to strong phonon scattering from the grain boundaries and nanoinclusions. Here, we report the incorporation of Cu2Se into Bi0.5Sb1.5Te3 (Bi0.5Sb1.5Te3-xCu2Se, where x = 0, 0.1, 0.3, 0.5 and 1.0wt%) synthesized by a solid-state reaction. The thermoelectric performance of Bi0.5Sb1.5Te3 (BST) was synergistically enhanced by the energy-filtering effect and phonon scattering. Cu2Se dispersal into the BST matrix caused enhanced carrier transport properties at the grain boundary interfaces and also a drastic reduction in thermal conductivity. High increase in electrical conductivity was attributed to strong electron scattering at large interface barriers. Low thermal conductivity of 0.63 W m-1 K-1 at 311 K was obtained for BST-0.1wt%Cu2Se. Low thermal conductivity originated from enhanced phonon scattering by Cu2Se as well as phase boundaries between BST and Cu2Se nanophases. These generated a high figure of merit zT of 1.32 at 311 K for 0.1wt%Cu2Se in the BST matrix, significantly higher than pristine BST (zT = 1.19 at 311 K). Results suggested that incorporation of Cu2Se into the BST matrix effectively improved low-temperature thermoelectric power generation of Bi2Te3-based thermoelectric material. © 2023, The Authors. All rights reserved.

关键词： Phonon scattering

来源：评论

学校读者我要写书评

暂无评论

Layer-dependent optically induced spin polarization in InSe

引用

Physical Review B 2023年第11期107卷 115304-115304页

作者： Jovan Nelson Teodor K. Stanev Dmitry Lebedev Trevor LaMountain J. Tyler Gish Hongfei Zeng Hyeondeok Shin Olle Heinonen Kenji Watanabe Takashi Taniguchi Mark C. Hersam Nathaniel P. Stern Applied Physics Program Northwestern University Evanston Illinois 60208 USA Department of Physics and Astronomy Northwestern University Evanston Illinois 60208 USA Department of Material Science and Engineering Northwestern University Evanston Illinois 60208 USA Computational Science Division Argonne National Laboratory Lemont Illinois 60439 USA Material Science Division Argonne National Laboratory Lemont Illinois 60439 USA Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan Department of Chemistry Northwestern University Evanston Illinois 60208 USA Department of Electrical Engineering and Computer Science Northwestern University Evanston Illinois 60208 USA

Optical control of spin in semiconductors has been pioneered using nanostructures of III-V and II-VI semiconductors, but the emergence of two-dimensional van der Waals materials offers an alternative low-dimensional platform for spintronic phenomena. Indium selenide (InSe), a group-III monochalcogenide van der Waals material, has shown promise for optoelectronics due to its high electron mobility, tunable direct band gap, and quantum transport. In addition to these confirmed properties, there are predictions of spin-dependent optical selection rules, suggesting the potential for all-optical excitation and control of spin in a two-dimensional layered material. Despite these predictions, layer-dependent optical spin phenomena in InSe have yet to be explored. Here, we present measurements of layer-dependent optical spin dynamics in few-layer and bulk InSe. Polarized photoluminescence reveals layer-dependent optical orientation of spin, thereby demonstrating the optical selection rules in few-layer InSe. Spin dynamics are also studied in many-layer InSe using time-resolved Kerr rotation spectroscopy. By applying out-of-plane and in-plane static magnetic fields for polarized emission measurements and Kerr measurements, respectively, the g factor for InSe was extracted. Further investigations are done by calculating precession values using a k·p model, which is supported by ab initio density functional theory. Comparison of predicted precession rates with experimental measurements highlights the importance of excitonic effects in InSe for understanding spin dynamics. Optical orientation of spin is an important prerequisite for optospintronic phenomena and devices, and these first demonstrations of layer-dependent optical excitation of spins in InSe lay the foundation for combining layer-dependent spin properties with advantageous electronic properties found in this material.

关键词： Magneto-optics Spin dynamics Chalcogenides Layered semiconductors Van der Waals systems Density functional theory Kerr effect Photoluminescence k dot p method

来源：评论

学校读者我要写书评

暂无评论

Band gap and band alignment prediction of nitride based semiconductors using machine learning

arXiv

引用

arXiv 2018年

作者： Huang, Yang Yu, Changyou Chen, Weiguang Liu, Yuhuai Li, Chong Niu, Chunyao Wang, Fei Jia, Yu International Laboratory for Quantum Functional Materials of Henan School of Physics and Engineering Zhengzhou University Zhengzhou450001 China Materials Science and Engineering Program University of California San Diego La JollaCA92093 United States National Center for International Joint Research of Electronic Materials and Systems School of Information Engineering Zhengzhou University Zhengzhou450001 China Quantum Materials Research Center College of Physics and Electronic Engineering Zhengzhou Normal University Zhengzhou450044 China Institute of Materials and Systems for Sustainability Nagoya University Nagoya464-8603 Japan Key Laboratory for Special Functional Material of Ministry of Education School of Materials Science Henan University Kaifeng475004 China

Nitride has been drawing much attention due to its wide range of applications in optoelectronics and remains plenty of room for materials design and discovery. Here, a large set of nitrides have been designed, with their band gap and alignment being studied by first-principles calculations combined with machine learning. Band gap and band offset against wurtzite GaN accurately calculated by the combination of screened hybrid functional of HSE and DFT-PBE were used to train and test machine learning models. After comparison among different techniques of machine learning, when elemental properties are taken as features, support vector regression (SVR) with radial kernel performs best for predicting both band gap and band offset with prediction root mean square error (RMSE) of 0.298 eV and 0.183 eV, respectively. The former is within HSE calculation uncertainty and the latter is small enough to provide reliable predictions. Additionally, when band gap calculated by DFT-PBE was added into the feature space, band gap prediction RMSE decreases to 0.099 eV. Through a feature engineering algorithm, elemental feature space based band gap prediction RMSE further drops by around 0.005 eV and the relative importance of elemental properties for band gap prediction was revealed. Finally, band gap and band offset of all designed nitrides were predicted and two trends were noticed that as the number of cation types increases, band gap tends to narrow down while band offset tends to go up. The predicted results will be a useful guidance for precise investigation on nitride engineering. Copyright © 2018, The Authors. All rights reserved.

关键词： Energy gap

来源：评论

学校读者我要写书评

暂无评论

Spatiotemporally controlled room temperature exciton transport under dynamic pressure

arXiv

引用

arXiv 2021年

作者： Datta, Kanak Lyu, Zhengyang Li, Zidong Taniguchi, Takashi Watanabe, Kenji Deotare, Parag B. Department of Electrical and Computer Engineering College of Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program College of Literature Science and Arts University of Michigan Ann ArborMI48109 United States International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Ibaraki305-0044 Japan Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan

Two-dimensional transition metal dichalcogenides (TMDs) provide an attractive platform for studying strain dependent exciton transport at room temperature due to large exciton binding energy and strong bandgap sensitivity to mechanical stimuli. Here, we use Rayleigh type surface acoustic wave (SAW) to demonstrate controlled and directional exciton transport under weak coupling regime at room temperature. We screen the in-plane piezoelectric field using photogenerated carriers to study transport under type-I bandgap modulation and measure a maximum exciton drift velocity of 600 m/s. Furthermore, we demonstrate precise steering of exciton flux by controlling the relative phase between the input RF excitation and exciton photogenerations. The results provide important insight into the weak coupling regime between dynamic strain wave and room temperature excitons in a 2D semiconductor system and pave way to exciting applications of excitonic devices in data communication and processing, sensing and energy conversion. Copyright © 2021, The Authors. All rights reserved.

关键词： Excitons

来源：评论

学校读者我要写书评

暂无评论

Mixed-dimensional moiré systems of graphitic thin films with a twisted interface

arXiv

引用

arXiv 2022年

作者： Waters, Dacen Thompson, Ellis Arreguin-Martinez, Esmeralda Fujimoto, Manato Ren, Yafei Watanabe, Kenji Taniguchi, Takashi Cao, Ting Xiao, Di Yankowitz, Matthew Department of Physics University of Washington SeattleWA98195 United States Intelligence Community Postdoctoral Research Fellowship Program University of Washington SeattleWA98195 United States Department of Materials Science and Engineering University of Washington SeattleWA98195 United States Department of Physics Osaka University Osaka560-0043 Japan Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan

Moiré patterns formed by stacking atomically-thin van der Waals crystals with a relative twist angle can give rise to dramatic new physical properties [1, 2]. The study of moiré materials has so far been limited to structures comprising no more than a few vdW sheets, since a moiré pattern localized to a single two-dimensional interface is generally assumed to be incapable of appreciably modifying the properties of a bulk three-dimensional crystal. Layered semimetals such as graphite offer a unique platform to challenge this paradigm, owing to distinctive properties arising from their nearly-compensated electron and hole bulk doping. Here, we perform transport measurements of dual-gated devices constructed by slightly rotating a monolayer graphene sheet atop a thin bulk graphite crystal. We find that the moiré potential transforms the electronic properties of the entire bulk graphitic thin film. At zero and small magnetic fields, transport is mediated by a combination of gate-tunable moiré and graphite surface states, as well as coexisting semimetallic bulk states that do not respond to gating. At high field, the moiré potential hybridizes with the graphitic bulk states owing to the unique properties of the two lowest Landau bands of graphite. These Landau bands facilitate the formation of a single quasi–two-dimensional hybrid structure in which the moiré and bulk graphite states are inextricably mixed. Our results establish twisted graphene-graphite as the first in a new class of mixed-dimensional moiré materials. Copyright © 2022, The Authors. All rights reserved.

关键词： Thin films

来源：评论

学校读者我要写书评

暂无评论

Quantum-Well Bound States in Graphene Heterostructure Interfaces

引用

Physical Review Letters 2021年第8期127卷 086805-086805页

作者： Zhongwei Dai (代中伟) Zhaoli Gao Sergey S. Pershoguba Nikhil Tiwale Ashwanth Subramanian Qicheng Zhang Calley Eads Samuel A. Tenney Richard M. Osgood Chang-Yong Nam Jiadong Zang A. T. Charlie Johnson Jerzy T. Sadowski Center for Functional Nanomaterials Brookhaven National Laboratory Upton New York 11973 USA Department of Physics and Astronomy University of Pennsylvania Philadelphia Pennsylvania 19104 USA Department of Biomedical Engineering The Chinese University of Hong Kong Hong Kong China Department of Physics and Astronomy and Materials Science Program University of New Hampshire Durham New Hampshire 03824 USA Department of Materials Science and Chemical Engineering Stony Brook University Stony Brook New York 11794 USA Department of Electrical Engineering Columbia University New York New York 10027 USA

We present experimental evidence of electronic and optical interlayer resonances in graphene van der Waals heterostructure interfaces. Using the spectroscopic mode of a low-energy electron microscope (LEEM), we characterized these interlayer resonant states up to 10 eV above the vacuum level. Compared with nontwisted, AB-stacked bilayer graphene (AB BLG), an ≈0.2 Å increase was found in the interlayer spacing of 30° twisted bilayer graphene (30°-tBLG). In addition, we used Raman spectroscopy to probe the inelastic light-matter interactions. A unique type of Fano resonance was found around the D and G modes of the graphene lattice vibrations. This anomalous, robust Fano resonance is a direct result of quantum confinement and the interplay between discrete phonon states and the excitonic continuum.

关键词： Electronic structure Graphene Heterostructures Low-energy electron microscopy Raman spectroscopy

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：