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Recent progresses of quantum confinement in graphene quantum dots

Frontiers of physics 2022年第3期17卷 9-33页

作者： Si-Yu Li Lin He Key Laboratory for Micro-Nano Physics and Technology of Hunan Province College of Materials Science and EngineeringHunan UniversityChangsha 410082China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China

Graphene quantum dots (GQDs) not only have potential applications on spin qubit, but also serve as essential platforms to study the fundamental properties of Dirac fermions, such as Klein tunneling and Berry phase. By now, the study of quantum confinement in GQDs still attract much attention in condensed matter physics. In this article, we review the experimental progresses on quantum confinement in GQDs mainly by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). Here, the GQDs are divided into Klein GQDs, bound-state GQDs and edge-terminated GQDs according to their different confinement strength. Based on the realization of quasi-bound states in Klein GQDs, external perpendicular magnetic field is utilized as a manipulation approach to trigger and control the novel properties by tuning Berry phase and electron–electron (e–e) interaction. The tip-induced edge-free GQDs can serve as an intuitive mean to explore the broken symmetry states at nanoscale and single-electron accuracy, which are expected to be used in studying physical properties of different two-dimensional materials. Moreover, high-spin magnetic ground states are successfully introduced in edge-terminated GQDs by designing and synthesizing triangulene zigzag nanographenes.

关键词： graphene quantum dot scanning tunneling microscopy scanning tunneling spectroscopy quasi-bound state bound state triangulene

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Growth of CySi1-x-ySnx Alloys for Low-Cost High-Efficiency Multi-Junction Solar Cells

Growth of CySi1-x-ySnx Alloys for Low-Cost High-Efficiency M...

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IEEE Conference Photovoltaic Specialists (PVSC)

作者： Seyedeh Fahimeh Banihashemian Mohammad Mahmoudi Aboozar Mosleh Hameed A. Naseem Department of Electrical Engineering University of Arkansas Fayetteville AR USA Materials Science & Engineering Program University of Arkansas Fayetteville AR USA

ISBN: (数字)9781665464260

ISBN: (纸本)9781665475822

The future demand for high efficiency solar cell necessitates a breakthrough in development of multi-junction cells. Presently, single junction solar cells dominate the market due to the high production expenses associated with multi-junction variants. This study demonstrates growth and characterization of a new ternary material system of CSiSn that holds promise for fabricating high-efficiency multi-junction solar cells on a Si substrate.

关键词： Photovoltaic systems Tensile strain Photovoltaic cells Optical device fabrication Metals Production Silicon Optical materials Optical films Substrates

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A Microstructural Investigation of Sub-1 μm Copper Bonding Contact Structures in Die-to-Wafer Hybrid Bonding

A Microstructural Investigation of Sub-1 μm Copper Bonding ...

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Electronic Components and Technology Conference (ECTC)

作者： Sari Al Zerey Junghyun Cho Roy Yu Katsuyuki Sakuma Materials Science and Engineering Program Binghamton University (State University of New York) Binghamton NY USA Dept. of Mechanical Engineering and Materials Science and Engineering Program Binghamton University (State University of New York) Binghamton NY USA IBM Research Albany NY USA

ISBN: (数字)9798350375985

ISBN: (纸本)9798350375992

This study explored the fine pitch scalability of the die-to-die level vertical stacking through the Cu/SiO 2 hybrid bonding technique for chips with varying Cu contact diameters (0.8-4 μm) and pitch spacings (2-10 μm). It also addresses challenges associated with the scalability of hybrid bonding including the precise alignment of the top/bottom Cu pads. In addition, we seek a better understanding of the microstructural evolution and mechanical deformation of Cu grains during the hybrid bonding process. This involves microstructural characterization of the Cu films before and after the hybrid bonding via scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). In conclusion, this study offers some explanation on controlling mechanisms of the Cu-Cu bonding and highlights the desirable initial microstructural features and grain orientations of the Cu pads to improve the Cu-Cu bonding quality for hybrid bonding.

关键词： Scanning electron microscopy Deformation Scalability Electron backscatter diffraction Films Stacking Electronic components

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Porous-structure engineered spacer for high-throughput and rapidgrowth of high-quality graphene films

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Nano Research 2022年第11期15卷 9741-9746页

作者： Ziteng Ma Heng Chen Xiaofeng Song Buhang Chen Qin Li Yanglizhi Li Haiyang Liu Kaicheng Jia Shenghong Huang Luzhao Sun Zhongfan Liu Center for Nanochemistry Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Beijing Graphene Institute Beijing 100095China College of Materials Science and Technology Beijing University of Chemical TechnologyBeijing 100029China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China College of Energy Soochow Institute for Energy and Materials InnovationS(SIEMIS)Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou 215006China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China

Chemical vapor deposition(CVD)in conjunction with batch-to-batch manufacturing process is considered as the most promising technical route for mass-production of high-quality graphene *** improve the space utilization of the CVD chamber and increase the throughput per batch,stacking of the Cu foil substrates is efficient,but suffers from the problems of adjacent fusion and the poor ***,we demonstrate an efficient strategy for high-throughput and rapid growth of high-quality graphene by alternate stacking of Cu foils and porous carbon fiber paper(CFP).Relying on the unhindered mass-transfer through the pores of CFPs,full-covered high-quality graphene films on compact-stacked Cu foils were achieved within 2 *** fluid dynamics(CFD)simulation and isotope labeling technique were performed to explore the gas diffusion and graphene growth process in the confined space of the Cu-CFP *** work provides a feasible method for industrial production of graphene films,which may also be used for batch production of other two-dimensional materials.

关键词： graphene chemical vapor deposition fast growth high-throughput batch-to-batch production

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Acetic acid-and furfural-based adaptive evolution of Saccharomyces cerevisiae strains for improving stress tolerance and lignocellulosic ethanol production

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Chinese Journal of Chemical engineering 2024年第8期72卷 26-33页

作者： Omama Rehman Youduo Wu Quan Zhang Jin Guo Cuihuan Sun Huipeng Gao Yaqing Xu Rui Xu Ayesha Shahid Chuang Xue State Key Laboratory of Fine Chemicals Frontiers Science Centre for Smart Materials Oriented Chemical EngineeringEngineering Research Center of Application and Transformation for Synthetic BiologySchool of BioengineeringDalian University of TechnologyDalian 116024China Ningbo Institute of Dalian University of Technology Ningbo 315016China SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co. Ltd.Dalian 116041China Microbial Research Institute of Liaoning Province Chaoyang 122000China Yunnan Provincial Rural Energy Engineering Key Laboratory Kunming 650600China US-Pak Center for Advanced Studies in Agriculture and Food Security University of AgricultureFaisalabadPakistan

Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol *** negatively impact cell growth,glucose uptake and ethanol biosynthesis of Saccharomyces cerevisiae *** of industrial *** strains with high tolerance towards these inhibitors is thus critical for efficient lignocellulosic ethanol *** this study,the acetic acid or furfural tolerance of different *** strains could be significantly enhanced after adaptive evolution via serial cultivation for 40 generations under stress *** acetic acid-based adaptive strain SPSC01-TA9 produced 30.5 g·L^(-1)ethanol with a yield of 0.46 g·g^(-1)in the presence of 9 g·L^(-1)acetic acid,while the acetic acid/furfural-based adaptive strain SPSC01-TAF94 produced more ethanol of 36.2 g·L^(-1)with increased yield up to 0.49 g·g^(-1)in the presence of both 9 g·L^(-1)acetic acid and 4 g·L^(-1)*** improvements were also observed during non-detoxified corn stover hydrolysate culture by SPSC01-TAF94,which achieved ethanol production and yield of 29.1 g·L^(-1)and 0.49 g·g^(-1),respectively,the growth and fermentation efficiency of acetic acid/furfural-based adaptive strain in hydrolysate was 95%higher than those of wildtype strains,indicating the acetic acid-and furfural-based adaptive evolution strategy could be an effective approach for improving lignocellulosic ethanol *** adapted strains developed in this study with enhanced tolerance against acetic acid and furfural could be potentially contribute to economically feasible and sustainable lignocellulosic biorefinery.

关键词： Saccharomyces cerevisiae Lignocellulosic ethanol production Adaptive evolution Acetic acid Furfural

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Copper acetate-facilitated transfer-free growth of high-quality graphene for hydrovoltaic generators

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National science Review 2022年第7期9卷 71-79页

作者： Jingyuan Shan Sunmiao Fang Wendong Wang Wen Zhao Rui Zhang Bingzhi Liu Li Lin Bei Jiang Haina Ci Ruojuan Liu Wen Wang Xiaoqin Yang Wenyue Guo Mark H.Rümmeli Wanlin Guo Jingyu Sun Zhongfan Liu Center for Nanochemistry (CNC) Beijing Science and Engineering Center for Nanocarbons Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University Academy for Advanced Interdisciplinary Studies Peking University Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education State Key Laboratory of Mechanics and Control of Mechanical Structures Institute of Nanoscience Nanjing University of Aeronautics and Astronautics Department of Physics and Astronomy University of Manchester School of Materials Science and Engineering China University of Petroleum (East China) College of Energy Soochow Institute for Energy and Materials Innovations (SIEMIS)Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy TechnologiesSoochow University Beijing Graphene Institute (BGI)

Direct synthesis of high-quality graphene on dielectric substrates without a transfer process is of vital importance for a variety of *** strategies for boosting high-quality graphene growth,such as remote metal catalyzation,are limited by poor performance with respect to the release of metal catalysts and hence suffer from a problem with metal ***,we report an effective approach that utilizes a metal-containing species,copper acetate,to continuously supply copper clusters in a gaseous form to aid transfer-free growth of graphene over a wafer *** thus-derived graphene films were found to show reduced multilayer density and improved electrical performance and exhibited a carrier mobility of8500 ***,droplet-based hydrovoltaic electricity generator devices based on directly grown graphene were found to exhibit robust voltage output and long cyclic stability,in stark contrast to their counterparts based on transferred graphene,demonstrating the potential for emerging energy harvesting *** work presented here offers a promising solution to organize the metal catalytic booster toward transfer-free synthesis of high-quality graphene and enable smart energy generation.

关键词： chemical vapor deposition graphene copper acetate hydrovoltaic electricity generator transfer-free growth

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Using a Mixed Solvent to Improve the Morphology of Thin Films, a One-Step Method is Employed to form Three-Dimensional Lead-Free Perovskite Solar Cells 18

Using a Mixed Solvent to Improve the Morphology of Thin Film...

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18th IEEE Nanotechnology materials and Devices Conference, NMDC 2023

作者： Huang, Yi Cheng Chen, Yen Shuo Tseng, Pin Chia Lin, Ching Chung You, Hsin Chiang Ko, Fu Hsiang National Yang Ming Chiao Tung University Department of Materials Science and Engineering Hsinchu30010 Taiwan The University of Tokyo Graduate School of Arts and Sciences Department of General System Studies Tokyo113-8654 Japan National Chin-Yi University of Technology Department of Electronic Science Engineering Taichung411030 Taiwan

ISBN: (纸本)9798350335460

Lead-free perovskite materials synthesized through solution-based methods have exhibited outstanding photovoltaic performance, along with appropriate bandgaps conducive to efficient solar energy absorption in solar cells. These attributes have been confirmed through the utilization of Power Conversion Efficiency (PCE), which measures the ability to convert absorbed light energy into electrical power. Their potential as environmentally friendly alternatives in solar cell technology has been established. Despite lead-based materials demonstrating high conversion efficiency in solar cell applications, their inherent toxicity raises environmental concerns. To address this issue, lead can be substituted with Bi3+ ions in lead-free perovskite materials, thereby reducing pollution and enhancing moisture resistance. The initial step involves optimizing the mixing ratio of Gamma-Butyrolactone (GBL) and Dimethyl Sulfoxide (DMSO) and combining them with appropriate precursors and Bi+ ions to form a Three-Dimensional (3D) CsBi3I10 perovskite structure. © 2023 IEEE.

关键词： Perovskite

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Bi selectively doped SrTiO3-x nanosheets enhance photocatalytic CO2 reduction under visible light

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Journal of Colloid and Interface science 2022年 611卷 137-148页

作者： Pan, Longkai Mei, Hui Zhu, Gangqiang Li, Shiping Xie, Xiaoqian Gong, Siwen Liu, Hongxia Jin, Zhipeng Gao, Jianzhi Cheng, Laifei Zhang, Litong Science and Technology on Thermostructural Composite Materials Laboratory School of Materials Science and Engineering Northwestern Polytechnical University Xi’ anShaanxi710072 China School of Physics and Information Technology Shaanxi Normal University Xi’ an710062 China Department of Physics and Oxide Research Center Hankuk University of Foreign Studies Yongin17035 Korea Republic of

Converting CO2 into chemical energy by using solar energy is an environmental strategy to achieve carbon neutrality. In this paper, two dimensionality (2D) SrTiO3-x nanosheets with oxygen vacancies were synthesized successfully. Oxygen vacancies will generate defect levels in the band structure of SrTiO3-x. So, SrTiO3-x nanosheets have good photocatalytic CO2 reduction performance under visible light. In order to further improve its photocatalytic efficiency, Bi was used to dope Sr site and Ti site in SrTiO3-x nanosheets respectively. It is found that Sr site is the adsorption site of CO2 molecules. When Bi replaced Sr, CO2 adsorption on the surface of SrTiO3-x nanosheets was weakened. When Bi replaced Ti, there has no effect on CO2 adsorption. Due to the synergistic effect of Bi doping, oxygen vacancies, and Sr active site, the 1.0% Bi-doped Ti site in SrTiO3-x (1.0% Bi-Ti-STO) had the best photocatalytic performance under visible light (λ ≥ 420 nm). CO and CH4 yields were 5.58 umol/g/h and 0.36 umol/g/h. Photocatalytic CO2 reduction path has always been the focus of exploration. The in-situ FTIR spectrum proved the step of photocatalytic CO2 reduction and COO– and COOH are important intermediates in the photocatalytic CO2 reaction. © 2021 Elsevier Inc.

关键词： Nanosheets

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CNN-Based Broad Learning for Cross-Domain Emotion Classification

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Tsinghua science and Technology 2023年第2期28卷 360-369页

作者： Rong Zeng Hongzhan Liu Sancheng Peng Lihong Cao Aimin Yang Chengqing Zong Guodong Zhou Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices South China Normal UniversityGuangzhou 511400China Laboratory of Language Engineering and Computing Guangdong University of Foreign StudiesGuangzhou 510006China School of Computer Science and Intelligence Education Lingnan Normal UniversityGuangzhou 510006China National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of SciencesBeijing 100190China School of Computer Science and Technology Soochow UniversitySuzhou 215031China

Cross-domain emotion classification aims to leverage useful information in a source domain to help predict emotion polarity in a target domain in a unsupervised or semi-supervised *** to the domain discrepancy,an emotion classifier trained on source domain may not work well on target *** researchers have focused on traditional cross-domain sentiment classification,which is coarse-grained emotion ***,the problem of emotion classification for cross-domain is rarely *** this paper,we propose a method,called convolutional neural network(CNN)based broad learning,for cross-domain emotion classification by combining the strength of CNN and broad *** first utilized CNN to extract domain-invariant and domain-specific features simultaneously,so as to train two more efficient classifiers by employing broad ***,to take advantage of these two classifiers,we designed a co-training model to boost together for ***,we conducted comparative experiments on four datasets for verifying the effectiveness of our proposed *** experimental results show that the proposed method can improve the performance of emotion classification more effectively than those baseline methods.

关键词： cross-domain emotion classification CNN broad learning classifier co-training

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In-plane Wilson loop for measurement of quantized non-Abelian Berry flux

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Physical Review B 2024年第19期109卷 195149-195149页

作者： Alexander C. Tyner Shouvik Sur Qunfei Zhou Danilo Puggioni Pierre Darancet James M. Rondinelli Pallab Goswami Graduate Program in Applied Physics Northwestern University Evanston Illinois 60208 USA Department of Physics and Astronomy Northwestern University Evanston Illinois 60208 USA Materials Research Science and Engineering Center Northwestern University Evanston Illinois 60208 USA Center for Nanoscale Materials Argonne National Laboratory Argonne Illinois 60439 USA Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA Northwestern Argonne Institute for Science and Engineering Evanston Illinois 60208 USA

Band topology of anomalous quantum Hall insulators can be precisely addressed by computing the Chern numbers of constituent nondegenerate bands, describing the presence of quantized, Abelian Berry flux through the two-dimensional Brillouin zone. Can Berry flux be captured for the SU(2) Berry connection of two-fold degenerate bands in spinful materials preserving space-inversion (P) and time-reversal (T) symmetries without detailed knowledge of underlying basis? We address this question by investigating the correspondence between a non-Abelian generalization of Stokes' theorem and the manifestly gauge-invariant eigenvalues of Wilson loops computed along in-plane contours which preserve the underlying crystalline symmetry. The importance of this correspondence is elucidated by performing natural number resolved classification of ab initio band structures of three-dimensional, Dirac materials. Our work underscores how identification of quantized Berry flux, both Abelian and non-Abelian, offers a unified framework for addressing first-order and higher-order topology of insulators and semimetals.

关键词： Electronic structure of atoms & molecules First-principles calculations Topological insulators

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