Liu Zheng
Degree: PhD
Position: Associate Professor
Affiliation: NTU - School of Materials Science & Engineering
Research Type: Experiment
Office: N4.1-01.10
Email: z.liu@ntu.edu.sg
Contact: (65) 6513 7352
CA2DM Publications:
2022 |
Zhao, Xiaoxu; Qiao, Jingsi; Zhou, Xin; Chen, Hao; Tan, Jun You; Yu, Hongyi; Chan, Si Min; Li, Jing; Zhang, Henshui; Zhou, Jiadong; Dan, Jiadong; Liu, Zhen; Zhou, Wu; Liu, Zheng; Peng, Bo; Deng, Longjiang; Pennycook, Stephen John; Quek, Su Ying; Loh, Kian Ping Strong Moire Excitons in High-Angle Twisted Transition Metal Dichalcogenide Homobilayers with Robust Commensuration Journal Article NANO LETTERS , 22 (1), pp. 203-210, 2022, ISSN: 1530-6984. @article{ISI:000769996700029, title = {Strong Moire Excitons in High-Angle Twisted Transition Metal Dichalcogenide Homobilayers with Robust Commensuration }, author = {Xiaoxu Zhao and Jingsi Qiao and Xin Zhou and Hao Chen and Jun You Tan and Hongyi Yu and Si Min Chan and Jing Li and Henshui Zhang and Jiadong Zhou and Jiadong Dan and Zhen Liu and Wu Zhou and Zheng Liu and Bo Peng and Longjiang Deng and Stephen John Pennycook and Su Ying Quek and Kian Ping Loh}, doi = {10.1021/acs.nanolett.1c03622}, times_cited = {0}, issn = {1530-6984}, year = {2022}, date = {2022-01-12}, journal = {NANO LETTERS }, volume = {22}, number = {1}, pages = {203-210}, publisher = {AMER CHEMICAL SOC }, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA }, abstract = {The burgeoning field of twistronics, which concerns how changing the relative twist angles between two materials creates new optoelectronic properties, offers a novel platform for studying twist-angle dependent excitonic physics. Herein, by surveying a range of hexagonal phase transition metal dichalcogenides (TMD) twisted homobilayers, we find that 21.8 +/- 1.0 degrees-twisted (root 7a x root 7a) and 27.8 +/- 1.0 degrees-twisted (root 13a x root 13a) bilayers account for nearly 20% of the total population of twisted bilayers in solution-phase restacked bilayers and can be found also in chemical vapor deposition (CVD) samples. Examining the optical properties associated with these twisted angles, we found that 21.8 +/- 1.0 degrees twisted MoS2 bilayers exhibit an intense moire exciton peak in the photoluminescence (PL) spectra, originating from the refolded Brillouin zones. Our work suggests that commensurately twisted TMD homobilayers with short commensurate wavelengths can have interesting optoelectronic properties that are different from the small twist angle counterparts. }, keywords = {}, pubstate = {published}, tppubtype = {article} } The burgeoning field of twistronics, which concerns how changing the relative twist angles between two materials creates new optoelectronic properties, offers a novel platform for studying twist-angle dependent excitonic physics. Herein, by surveying a range of hexagonal phase transition metal dichalcogenides (TMD) twisted homobilayers, we find that 21.8 +/- 1.0 degrees-twisted (root 7a x root 7a) and 27.8 +/- 1.0 degrees-twisted (root 13a x root 13a) bilayers account for nearly 20% of the total population of twisted bilayers in solution-phase restacked bilayers and can be found also in chemical vapor deposition (CVD) samples. Examining the optical properties associated with these twisted angles, we found that 21.8 +/- 1.0 degrees twisted MoS2 bilayers exhibit an intense moire exciton peak in the photoluminescence (PL) spectra, originating from the refolded Brillouin zones. Our work suggests that commensurately twisted TMD homobilayers with short commensurate wavelengths can have interesting optoelectronic properties that are different from the small twist angle counterparts. |
2021 |
Zhao, Xiaoxu; Qiao, Jingsi; Zhou, Xin; Chen, Hao; Tan, Jun You; Yu, Hongyi; Chan, Si Min; Li, Jing; Zhang, Henshui; Zhou, Jiadong; Dan, Jiadong; Liu, Zhen; Zhou, Wu; Liu, Zheng; Peng, Bo; Deng, Longjiang; Pennycook, Stephen John; Quek, Su Ying; Loh, Kian Ping Strong Moire Excitons in High-Angle Twisted Transition Metal Dichalcogenide Homobilayers with Robust Commensuration Journal Article NANO LETTERS, 22 (1), pp. 203-210, 2021, ISSN: 1530-6984. @article{ISI:000734459700001, title = {Strong Moire Excitons in High-Angle Twisted Transition Metal Dichalcogenide Homobilayers with Robust Commensuration}, author = {Xiaoxu Zhao and Jingsi Qiao and Xin Zhou and Hao Chen and Jun You Tan and Hongyi Yu and Si Min Chan and Jing Li and Henshui Zhang and Jiadong Zhou and Jiadong Dan and Zhen Liu and Wu Zhou and Zheng Liu and Bo Peng and Longjiang Deng and Stephen John Pennycook and Su Ying Quek and Kian Ping Loh}, doi = {10.1021/acs.nanolett.1c03622}, times_cited = {0}, issn = {1530-6984}, year = {2021}, date = {2021-12-20}, journal = {NANO LETTERS}, volume = {22}, number = {1}, pages = {203-210}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {The burgeoning field of twistronics, which concerns how changing the relative twist angles between two materials creates new optoelectronic properties, offers a novel platform for studying twist-angle dependent excitonic physics. Herein, by surveying a range of hexagonal phase transition metal dichalcogenides (TMD) twisted homobilayers, we find that 21.8 +/- 1.0 degrees-twisted (root 7a x root 7a) and 27.8 +/- 1.0 degrees-twisted (root 13a x root 13a) bilayers account for nearly 20% of the total population of twisted bilayers in solution-phase restacked bilayers and can be found also in chemical vapor deposition (CVD) samples. Examining the optical properties associated with these twisted angles, we found that 21.8 +/- 1.0 degrees twisted MoS2 bilayers exhibit an intense moire exciton peak in the photoluminescence (PL) spectra, originating from the refolded Brillouin zones. Our work suggests that commensurately twisted TMD homobilayers with short commensurate wavelengths can have interesting optoelectronic properties that are different from the small twist angle counterparts.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The burgeoning field of twistronics, which concerns how changing the relative twist angles between two materials creates new optoelectronic properties, offers a novel platform for studying twist-angle dependent excitonic physics. Herein, by surveying a range of hexagonal phase transition metal dichalcogenides (TMD) twisted homobilayers, we find that 21.8 +/- 1.0 degrees-twisted (root 7a x root 7a) and 27.8 +/- 1.0 degrees-twisted (root 13a x root 13a) bilayers account for nearly 20% of the total population of twisted bilayers in solution-phase restacked bilayers and can be found also in chemical vapor deposition (CVD) samples. Examining the optical properties associated with these twisted angles, we found that 21.8 +/- 1.0 degrees twisted MoS2 bilayers exhibit an intense moire exciton peak in the photoluminescence (PL) spectra, originating from the refolded Brillouin zones. Our work suggests that commensurately twisted TMD homobilayers with short commensurate wavelengths can have interesting optoelectronic properties that are different from the small twist angle counterparts. |
Li, Peiyang; Zhang, Jiantian; Zhu, Chao; Shen, Wanfu; Hu, Chunguang; Fu, Wei; Yan, Luo; Zhou, Liujiang; Zheng, Lu; Lei, Hongxiang; Liu, Zheng; Zhao, Weina; Gao, Pingqi; Yu, Peng; Yang, Guowei Penta-PdPSe: A New 2D Pentagonal Material with Highly In-Plane Optical, Electronic, and Optoelectronic Anisotropy Journal Article ADVANCED MATERIALS, 33 (35), 2021, ISSN: 0935-9648. @article{ISI:000677212100001, title = {\textit{Penta}-PdPSe: A New 2D Pentagonal Material with Highly In-Plane Optical, Electronic, and Optoelectronic Anisotropy}, author = {Peiyang Li and Jiantian Zhang and Chao Zhu and Wanfu Shen and Chunguang Hu and Wei Fu and Luo Yan and Liujiang Zhou and Lu Zheng and Hongxiang Lei and Zheng Liu and Weina Zhao and Pingqi Gao and Peng Yu and Guowei Yang}, doi = {10.1002/adma.202102541}, times_cited = {0}, issn = {0935-9648}, year = {2021}, date = {2021-07-24}, journal = {ADVANCED MATERIALS}, volume = {33}, number = {35}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Due to their low-symmetry lattice characteristics and intrinsic in-plane anisotropy, 2D pentagonal materials, a new class of 2D materials composed entirely of pentagonal atomic rings, are attracting increasing research attention. However, the existence of these 2D materials has not been proven experimentally until the recent discovery of PdSe2. Herein, penta-PdPSe, a new 2D pentagonal material with a novel low-symmetry puckered pentagonal structure, is introduced to the 2D family. Interestingly, a peculiar polyanion of [Se-P-P-Se](4-) is discovered in this material, which is the biggest polyanion in 2D materials yet discovered. Strong intrinsic in-plane anisotropic behavior endows penta-PdPSe with highly anisotropic optical, electronic, and optoelectronic properties. Impressively, few-layer penta-PdPSe-based phototransistor not only achieves excellent electronic performances, a moderate electron mobility of 21.37 cm(2) V-1 s(-1) and a high on/off ratio of up to 10(8), but it also has a high photoresponsivity of approximate to 5.07 x 10(3) A W-1 at 635 nm, which is ascribed to the photogating effect. More importantly, penta-PdPSe also exhibits a large anisotropic conductance (sigma(max)/sigma(max) = 3.85) and responsivity (R-max/R-min = 6.17 at 808 nm), superior to most 2D anisotropic materials. These findings make penta-PdPSe an ideal material for the design of next-generation anisotropic devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Due to their low-symmetry lattice characteristics and intrinsic in-plane anisotropy, 2D pentagonal materials, a new class of 2D materials composed entirely of pentagonal atomic rings, are attracting increasing research attention. However, the existence of these 2D materials has not been proven experimentally until the recent discovery of PdSe2. Herein, penta-PdPSe, a new 2D pentagonal material with a novel low-symmetry puckered pentagonal structure, is introduced to the 2D family. Interestingly, a peculiar polyanion of [Se-P-P-Se](4-) is discovered in this material, which is the biggest polyanion in 2D materials yet discovered. Strong intrinsic in-plane anisotropic behavior endows penta-PdPSe with highly anisotropic optical, electronic, and optoelectronic properties. Impressively, few-layer penta-PdPSe-based phototransistor not only achieves excellent electronic performances, a moderate electron mobility of 21.37 cm(2) V-1 s(-1) and a high on/off ratio of up to 10(8), but it also has a high photoresponsivity of approximate to 5.07 x 10(3) A W-1 at 635 nm, which is ascribed to the photogating effect. More importantly, penta-PdPSe also exhibits a large anisotropic conductance (sigma(max)/sigma(max) = 3.85) and responsivity (R-max/R-min = 6.17 at 808 nm), superior to most 2D anisotropic materials. These findings make penta-PdPSe an ideal material for the design of next-generation anisotropic devices. |
2020 |
Wang, Xuewen; Fu, Wei; Gao, Guanhui; Mehay, Mandeep Singh; Zheng, Lu; Wang, Hong; Zhao, Wu; Loh, Kian Ping; Zhang, Ting; Huang, Wei; Liu, Zheng Self-cross-linked arrays enabled flexible mechanical sensors for monitoring the body tremor Journal Article NPJ FLEXIBLE ELECTRONICS, 4 (1), 2020. @article{ISI:000620869900001, title = {Self-cross-linked arrays enabled flexible mechanical sensors for monitoring the body tremor}, author = {Xuewen Wang and Wei Fu and Guanhui Gao and Mandeep Singh Mehay and Lu Zheng and Hong Wang and Wu Zhao and Kian Ping Loh and Ting Zhang and Wei Huang and Zheng Liu}, doi = {10.1038/s41528-020-0071-3}, times_cited = {0}, year = {2020}, date = {2020-05-06}, journal = {NPJ FLEXIBLE ELECTRONICS}, volume = {4}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Thin-film electronics played an important role in flexible healthcare sensor applications. The common status of their constituent blocks are solid film and network structures. However, the solid film could only sustain bend in a narrow range due to cracks, and the network structure decreased the sensitivity of flexion sensors due to the strong interactions between nanowires. New materials and technologies are urgently required for flexible sensing electronics, to produce the reliable data for assessment of the human body. Here, we report on a novel three-dimensional (3D) carbon nanorods array (CNA) that is characterized as vertically aligned nanorods and self-cross-linked junctions. We also demonstrate the CNA-based flexible healthcare sensors in monitoring the Parkinsonian tremors. Comparing with two-dimensional (2D) carbon nanotube networks and solid thin films, such self-cross-linked geometries are highly resistant to crack and fragmentation under strain. In the meantime, it shows high sensitivity and good stability (similar to 10,000 times) to detect the flexions. These CNA-based flexible devices are capable of recording low-frequency vibrations (<6Hz) and make it excellent to monitor the rest tremor of the human body, which is an initial symptom of Parkinson's disease. The 3D self-cross-linked CNA film shows great potential in the fabrication of cost-effective and durable flexible sensors for early diagnosis of disease by monitoring the health-related rest tremors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Thin-film electronics played an important role in flexible healthcare sensor applications. The common status of their constituent blocks are solid film and network structures. However, the solid film could only sustain bend in a narrow range due to cracks, and the network structure decreased the sensitivity of flexion sensors due to the strong interactions between nanowires. New materials and technologies are urgently required for flexible sensing electronics, to produce the reliable data for assessment of the human body. Here, we report on a novel three-dimensional (3D) carbon nanorods array (CNA) that is characterized as vertically aligned nanorods and self-cross-linked junctions. We also demonstrate the CNA-based flexible healthcare sensors in monitoring the Parkinsonian tremors. Comparing with two-dimensional (2D) carbon nanotube networks and solid thin films, such self-cross-linked geometries are highly resistant to crack and fragmentation under strain. In the meantime, it shows high sensitivity and good stability (similar to 10,000 times) to detect the flexions. These CNA-based flexible devices are capable of recording low-frequency vibrations (<6Hz) and make it excellent to monitor the rest tremor of the human body, which is an initial symptom of Parkinson's disease. The 3D self-cross-linked CNA film shows great potential in the fabrication of cost-effective and durable flexible sensors for early diagnosis of disease by monitoring the health-related rest tremors. |
Zhao, Xiaoxu; Song, Peng; Wang, Chengcai; Riis-Jensen, Anders C; Fu, Wei; Deng, Ya; Wan, Dongyang; Kang, Lixing; Ning, Shoucong; Dan, Jiadong; Venkatesan, T; Liu, Zheng; Zhou, Wu; Thygesen, Kristian S; Luo, Xin; Pennycook, Stephen J; Loh, Kian Ping Engineering covalently bonded 2D layered materials by self-intercalation Journal Article NATURE, 581 (7807), pp. 171-+, 2020, ISSN: 0028-0836. @article{ISI:000532836000027, title = {Engineering covalently bonded 2D layered materials by self-intercalation}, author = {Xiaoxu Zhao and Peng Song and Chengcai Wang and Anders C Riis-Jensen and Wei Fu and Ya Deng and Dongyang Wan and Lixing Kang and Shoucong Ning and Jiadong Dan and T Venkatesan and Zheng Liu and Wu Zhou and Kristian S Thygesen and Xin Luo and Stephen J Pennycook and Kian Ping Loh}, doi = {10.1038/s41586-020-2241-9}, times_cited = {0}, issn = {0028-0836}, year = {2020}, date = {2020-05-01}, journal = {NATURE}, volume = {581}, number = {7807}, pages = {171-+}, publisher = {NATURE RESEARCH}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Two-dimensional (2D) materials(1-5) offer a unique platform from which to explore the physics of topology and many-body phenomena. New properties can be generated by filling the van der Waals gap of 2D materials with intercalants(6,7); however, post-growth intercalation has usually been limited to alkali metals(8-10). Here we show that the self-intercalation of native atoms(11,12) into bilayer transition metal dichalcogenides during growth generates a class of ultrathin, covalently bonded materials, which we name ic-2D. The stoichiometry of these materials is defined by periodic occupancy patterns of the octahedral vacancy sites in the van der Waals gap, and their properties can be tuned by varying the coverage and the spatial arrangement of the filled sites(7,13). By performing growth under high metal chemical potential(14,15) we can access a range of tantalum-intercalated TaS(Se)(y), including 25% Ta-intercalated Ta9S16, 33.3% Ta-intercalated Ta7S12, 50% Ta-intercalated Ta10S16, 66.7% Ta-intercalated Ta8Se12 (which forms a Kagome lattice) and 100% Ta-intercalated Ta9Se12. Ferromagnetic order was detected in some of these intercalated phases. We also demonstrate that self-intercalated V11S16, In11Se16 and FexTey can be grown under metal-rich conditions. Our work establishes self-intercalation as an approach through which to grow a new class of 2D materials with stoichiometry- or composition-dependent properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two-dimensional (2D) materials(1-5) offer a unique platform from which to explore the physics of topology and many-body phenomena. New properties can be generated by filling the van der Waals gap of 2D materials with intercalants(6,7); however, post-growth intercalation has usually been limited to alkali metals(8-10). Here we show that the self-intercalation of native atoms(11,12) into bilayer transition metal dichalcogenides during growth generates a class of ultrathin, covalently bonded materials, which we name ic-2D. The stoichiometry of these materials is defined by periodic occupancy patterns of the octahedral vacancy sites in the van der Waals gap, and their properties can be tuned by varying the coverage and the spatial arrangement of the filled sites(7,13). By performing growth under high metal chemical potential(14,15) we can access a range of tantalum-intercalated TaS(Se)(y), including 25% Ta-intercalated Ta9S16, 33.3% Ta-intercalated Ta7S12, 50% Ta-intercalated Ta10S16, 66.7% Ta-intercalated Ta8Se12 (which forms a Kagome lattice) and 100% Ta-intercalated Ta9Se12. Ferromagnetic order was detected in some of these intercalated phases. We also demonstrate that self-intercalated V11S16, In11Se16 and FexTey can be grown under metal-rich conditions. Our work establishes self-intercalation as an approach through which to grow a new class of 2D materials with stoichiometry- or composition-dependent properties. |
2019 |
Zeng, Qingsheng; Sun, Bo; Du, Kezhao; Zhao, Weiyun; Yu, Peng; Zhu, Chao; Xia, Juan; Chen, Yu; Cao, Xun; Yan, Qingyu; Shen, Zexiang; Yu, Ting; Long, Yi; Koh, Yee Kan; Liu, Zheng Highly anisotropic thermoelectric properties of black phosphorus crystals Journal Article 2D MATERIALS, 6 (4), 2019, ISSN: 2053-1583. @article{ISI:000474688300004, title = {Highly anisotropic thermoelectric properties of black phosphorus crystals}, author = {Qingsheng Zeng and Bo Sun and Kezhao Du and Weiyun Zhao and Peng Yu and Chao Zhu and Juan Xia and Yu Chen and Xun Cao and Qingyu Yan and Zexiang Shen and Ting Yu and Yi Long and Yee Kan Koh and Zheng Liu}, doi = {10.1088/2053-1583/ab2816}, times_cited = {3}, issn = {2053-1583}, year = {2019}, date = {2019-10-01}, journal = {2D MATERIALS}, volume = {6}, number = {4}, publisher = {IOP PUBLISHING LTD}, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, abstract = {Black phosphorus captures enormous research attention on the anisotropic properties due to its orthorhombic crystal structure. Here the in-plane anisotropic thermoelectric behaviors of bulk black phosphorus crystals in the temperature range from 300 K to 600 K are reported for the first time. Based on the home-grown big size and high-quality black phosphorus crystals, the electrical conductivity and Seebeck coefficient are simultaneously measured by a ZEM-3 instrument system, and the thermal conductivity is measured by time-domain thermoreflectance (TDTR). For each individual parameter, the values along the zigzag and armchair directions show the same temperature-dependent trend. However, the electrical conductivity along the armchair direction is similar to two times of that along the zigzag direction, while the thermal conductivity along the armchair direction is only similar to one third of that along the zigzag direction. Furthermore, the Seebeck coefficients show almost isotropic behavior. As a result, the figure of merit ZT along the armchair direction is as large as similar to 5.5 times of that along the zigzag direction, exhibiting high anisotropy. The results of intrinsic, orientation-dependent thermoelectric behaviors not only shed light on the fundamental physical properties of black phosphorus but also provide guidelines in the device design for potential thermoelectric applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Black phosphorus captures enormous research attention on the anisotropic properties due to its orthorhombic crystal structure. Here the in-plane anisotropic thermoelectric behaviors of bulk black phosphorus crystals in the temperature range from 300 K to 600 K are reported for the first time. Based on the home-grown big size and high-quality black phosphorus crystals, the electrical conductivity and Seebeck coefficient are simultaneously measured by a ZEM-3 instrument system, and the thermal conductivity is measured by time-domain thermoreflectance (TDTR). For each individual parameter, the values along the zigzag and armchair directions show the same temperature-dependent trend. However, the electrical conductivity along the armchair direction is similar to two times of that along the zigzag direction, while the thermal conductivity along the armchair direction is only similar to one third of that along the zigzag direction. Furthermore, the Seebeck coefficients show almost isotropic behavior. As a result, the figure of merit ZT along the armchair direction is as large as similar to 5.5 times of that along the zigzag direction, exhibiting high anisotropy. The results of intrinsic, orientation-dependent thermoelectric behaviors not only shed light on the fundamental physical properties of black phosphorus but also provide guidelines in the device design for potential thermoelectric applications. |
2018 |
Kutty, Govindan R; Sreejith, Sivaramapanicker; Kong, Xianghua; He, Haiyong; Wang, Hong; Lin, Junhao; Suenaga, Kazu; Lim, Chwee Teck; Zhao, Yanli; Ji, Wei; Liu, Zheng A topologically substituted boron nitride hybrid aerogel for highly selective CO2 uptake Journal Article NANO RESEARCH, 11 (12), pp. 6325-6335, 2018, ISSN: 1998-0124. @article{ISI:000454367500019, title = {A topologically substituted boron nitride hybrid aerogel for highly selective CO_{2} uptake}, author = {Govindan R Kutty and Sivaramapanicker Sreejith and Xianghua Kong and Haiyong He and Hong Wang and Junhao Lin and Kazu Suenaga and Chwee Teck Lim and Yanli Zhao and Wei Ji and Zheng Liu}, doi = {10.1007/s12274-018-2156-z}, times_cited = {0}, issn = {1998-0124}, year = {2018}, date = {2018-12-01}, journal = {NANO RESEARCH}, volume = {11}, number = {12}, pages = {6325-6335}, publisher = {TSINGHUA UNIV PRESS}, address = {TSINGHUA UNIV, RM A703, XUEYAN BLDG, BEIJING, 100084, PEOPLES R CHINA}, abstract = {A topologically mediated synthesis of porous boron nitride aerogel has been experimentally and theoretically investigated for carbon dioxide (CO2) uptake. Replacement of the carbon atoms in a precursor aerogel of graphene oxide and carbon nanotubes was achieved using an elemental substitution reaction, to obtain a boron and nitrogen framework. The newly prepared BN aerogel possessed a specific surface area of 716.56 m(2)/g and exhibited an unprecedented twenty-fold increase in CO2 uptake over N-2, adsorbing 100 cc/g at 273 K and 80 cc/g in ambient conditions, as verified by adsorption isotherms via the multipoint Brunauer-Emmett-Teller (BET) method. Density functional theory calculations were performed to give hints on the mechanism of such high selectivity of CO2 over N-2 adsorption in BN aerogel, which may be due to the interaction between the intrinsic polar nature of B-N bonds and the high quadrupole moment of CO2 over N-2.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A topologically mediated synthesis of porous boron nitride aerogel has been experimentally and theoretically investigated for carbon dioxide (CO2) uptake. Replacement of the carbon atoms in a precursor aerogel of graphene oxide and carbon nanotubes was achieved using an elemental substitution reaction, to obtain a boron and nitrogen framework. The newly prepared BN aerogel possessed a specific surface area of 716.56 m(2)/g and exhibited an unprecedented twenty-fold increase in CO2 uptake over N-2, adsorbing 100 cc/g at 273 K and 80 cc/g in ambient conditions, as verified by adsorption isotherms via the multipoint Brunauer-Emmett-Teller (BET) method. Density functional theory calculations were performed to give hints on the mechanism of such high selectivity of CO2 over N-2 adsorption in BN aerogel, which may be due to the interaction between the intrinsic polar nature of B-N bonds and the high quadrupole moment of CO2 over N-2. |
Zhou, Jiadong; Lin, Junhao; Huang, Xiangwei; Zhou, Yao; Chen, Yu; Xia, Juan; Wang, Hong; Xie, Yu; Yu, Huimei; Lei, Jincheng; Wu, Di; Liu, Fucai; Fu, Qundong; Zeng, Qingsheng; Hsu, Chuang-Han; Yang, Changli; Lu, Li; Yu, Ting; Shen, Zexiang; Lin, Hsin; Yakobson, Boris I; Liu, Qian; Suenaga, Kazu; Liu, Guangtong; Liu, Zheng A library of atomically thin metal chalcogenides Journal Article NATURE, 556 (7701), pp. 355-+, 2018, ISSN: 0028-0836. @article{ISI:000430285200047, title = {A library of atomically thin metal chalcogenides}, author = {Jiadong Zhou and Junhao Lin and Xiangwei Huang and Yao Zhou and Yu Chen and Juan Xia and Hong Wang and Yu Xie and Huimei Yu and Jincheng Lei and Di Wu and Fucai Liu and Qundong Fu and Qingsheng Zeng and Chuang-Han Hsu and Changli Yang and Li Lu and Ting Yu and Zexiang Shen and Hsin Lin and Boris I Yakobson and Qian Liu and Kazu Suenaga and Guangtong Liu and Zheng Liu}, doi = {10.1038/s41586-018-0008-3}, times_cited = {0}, issn = {0028-0836}, year = {2018}, date = {2018-04-19}, journal = {NATURE}, volume = {556}, number = {7701}, pages = {355-+}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {Investigations of two-dimensional transition-metal chalcogenides (TMCs) have recently revealed interesting physical phenomena, including the quantum spin Hall effect(1,2), valley polarization(3,4) and two-dimensional superconductivity(5), suggesting potential applications for functional devices(6-10). However, of the numerous compounds available, only a handful, such as Mo- and W-based TMCs, have been synthesized, typically via sulfurization(11-15), selenization(16,17) and tellurization(18) of metals and metal compounds. Many TMCs are difficult to produce because of the high melting points of their metal and metal oxide precursors. Molten-salt-assisted methods have been used to produce ceramic powders at relatively low temperature(19) and this approach(20) was recently employed to facilitate the growth of monolayer WS2 and WSe2. Here we demonstrate that molten-salt-assisted chemical vapour deposition can be broadly applied for the synthesis of a wide variety of two-dimensional (atomically thin) TMCs. We synthesized 47 compounds, including 32 binary compounds (based on the transition metals Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Pt, Pd and Fe), 13 alloys (including 11 ternary, one quaternary and one quinary), and two heterostructured compounds. We elaborate how the salt decreases the melting point of the reactants and facilitates the formation of intermediate products, increasing the overall reaction rate. Most of the synthesized materials in our library are useful, as supported by evidence of superconductivity in our monolayer NbSe2 and MoTe2 samples(21,22) and of high mobilities in MoS2 and ReS2. Although the quality of some of the materials still requires development, our work opens up opportunities for studying the properties and potential application of a wide variety of two-dimensional TMCs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Investigations of two-dimensional transition-metal chalcogenides (TMCs) have recently revealed interesting physical phenomena, including the quantum spin Hall effect(1,2), valley polarization(3,4) and two-dimensional superconductivity(5), suggesting potential applications for functional devices(6-10). However, of the numerous compounds available, only a handful, such as Mo- and W-based TMCs, have been synthesized, typically via sulfurization(11-15), selenization(16,17) and tellurization(18) of metals and metal compounds. Many TMCs are difficult to produce because of the high melting points of their metal and metal oxide precursors. Molten-salt-assisted methods have been used to produce ceramic powders at relatively low temperature(19) and this approach(20) was recently employed to facilitate the growth of monolayer WS2 and WSe2. Here we demonstrate that molten-salt-assisted chemical vapour deposition can be broadly applied for the synthesis of a wide variety of two-dimensional (atomically thin) TMCs. We synthesized 47 compounds, including 32 binary compounds (based on the transition metals Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Pt, Pd and Fe), 13 alloys (including 11 ternary, one quaternary and one quinary), and two heterostructured compounds. We elaborate how the salt decreases the melting point of the reactants and facilitates the formation of intermediate products, increasing the overall reaction rate. Most of the synthesized materials in our library are useful, as supported by evidence of superconductivity in our monolayer NbSe2 and MoTe2 samples(21,22) and of high mobilities in MoS2 and ReS2. Although the quality of some of the materials still requires development, our work opens up opportunities for studying the properties and potential application of a wide variety of two-dimensional TMCs. |
Yu, Xuechao; Yu, Peng; Wu, Di; Singh, Bahadur; Zeng, Qingsheng; Lin, Hsin; Zhou, Wu; Lin, Junhao; Suenaga, Kazu; Liu, Zheng; Wang, Qi Jie Atomically thin noble metal dichalcogenide: a broadband mid-infrared semiconductor Journal Article NATURE COMMUNICATIONS, 9 , 2018, ISSN: 2041-1723. @article{ISI:000430286800020, title = {Atomically thin noble metal dichalcogenide: a broadband mid-infrared semiconductor}, author = {Xuechao Yu and Peng Yu and Di Wu and Bahadur Singh and Qingsheng Zeng and Hsin Lin and Wu Zhou and Junhao Lin and Kazu Suenaga and Zheng Liu and Qi Jie Wang}, doi = {10.1038/s41467-018-03935-0}, times_cited = {0}, issn = {2041-1723}, year = {2018}, date = {2018-04-18}, journal = {NATURE COMMUNICATIONS}, volume = {9}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {The interest in mid-infrared technologies surrounds plenty of important optoelectronic applications ranging from optical communications, biomedical imaging to night vision cameras, and so on. Although narrow bandgap semiconductors, such as Mercury Cadmium Telluride and Indium Antimonide, and quantum superlattices based on inter-subband transitions in wide bandgap semiconductors, have been employed for mid-infrared applications, it remains a daunting challenge to search for other materials that possess suitable bandgaps in this wavelength range. Here, we demonstrate experimentally for the first time that twodimensional (2D) atomically thin PtSe2 has a variable bandgap in the mid-infrared via layer and defect engineering. Here, we show that bilayer PtSe2 combined with defects modulation possesses strong light absorption in the mid-infrared region, and we realize a mid-infrared photoconductive detector operating in a broadband mid-infrared range. Our results pave the way for atomically thin 2D noble metal dichalcogenides to be employed in high-performance mid-infrared optoelectronic devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interest in mid-infrared technologies surrounds plenty of important optoelectronic applications ranging from optical communications, biomedical imaging to night vision cameras, and so on. Although narrow bandgap semiconductors, such as Mercury Cadmium Telluride and Indium Antimonide, and quantum superlattices based on inter-subband transitions in wide bandgap semiconductors, have been employed for mid-infrared applications, it remains a daunting challenge to search for other materials that possess suitable bandgaps in this wavelength range. Here, we demonstrate experimentally for the first time that twodimensional (2D) atomically thin PtSe2 has a variable bandgap in the mid-infrared via layer and defect engineering. Here, we show that bilayer PtSe2 combined with defects modulation possesses strong light absorption in the mid-infrared region, and we realize a mid-infrared photoconductive detector operating in a broadband mid-infrared range. Our results pave the way for atomically thin 2D noble metal dichalcogenides to be employed in high-performance mid-infrared optoelectronic devices. |
Zhou, Wu; Zhang, Yu-Yang; Chen, Jianyi; Li, Dongdong; Zhou, Jiadong; Liu, Zheng; Chisholm, Matthew F; Pantelides, Sokrates T; Loh, Kian Ping Dislocation-driven growth of two-dimensional lateral quantum-well superlattices Journal Article SCIENCE ADVANCES, 4 (3), 2018, ISSN: 2375-2548. @article{ISI:000431373300018, title = {Dislocation-driven growth of two-dimensional lateral quantum-well superlattices}, author = {Wu Zhou and Yu-Yang Zhang and Jianyi Chen and Dongdong Li and Jiadong Zhou and Zheng Liu and Matthew F Chisholm and Sokrates T Pantelides and Kian Ping Loh}, doi = {10.1126/sciadv.aap9096}, times_cited = {1}, issn = {2375-2548}, year = {2018}, date = {2018-03-01}, journal = {SCIENCE ADVANCES}, volume = {4}, number = {3}, publisher = {AMER ASSOC ADVANCEMENT SCIENCE}, address = {1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA}, abstract = {The advent of two-dimensional (2D) materials has led to extensive studies of heterostructures for novel applications. 2D lateral multiheterojunctions and superlattices have been recently demonstrated, but the available growth methods can only produce features with widths in the micrometer or, at best, 100-nm scale and usually result in rough and defective interfaces with extensive chemical intermixing. Widths smaller than 5 nm, which are needed for quantum confinement effects and quantum-well applications, have not been achieved. We demonstrate the growth of sub-2-nm quantum-well arrays in semiconductor monolayers, driven by the climb of misfit dislocations in a lattice-mismatched sulfide/selenide heterointerface. Density functional theory calculations provide an atom-by-atom description of the growth mechanism. The calculated energy bands reveal type II alignment suitable for quantum wells, suggesting that the structure could, in principle, be turned into a "conduit" of conductive nanoribbons for interconnects in future 2D integrated circuits via n-type modulation doping. This misfit dislocation-driven growth can be applied to different combinations of 2D monolayers with lattice mismatch, paving the way to a wide range of 2D quantum-well superlattices with controllable band alignment and nanoscale width.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The advent of two-dimensional (2D) materials has led to extensive studies of heterostructures for novel applications. 2D lateral multiheterojunctions and superlattices have been recently demonstrated, but the available growth methods can only produce features with widths in the micrometer or, at best, 100-nm scale and usually result in rough and defective interfaces with extensive chemical intermixing. Widths smaller than 5 nm, which are needed for quantum confinement effects and quantum-well applications, have not been achieved. We demonstrate the growth of sub-2-nm quantum-well arrays in semiconductor monolayers, driven by the climb of misfit dislocations in a lattice-mismatched sulfide/selenide heterointerface. Density functional theory calculations provide an atom-by-atom description of the growth mechanism. The calculated energy bands reveal type II alignment suitable for quantum wells, suggesting that the structure could, in principle, be turned into a "conduit" of conductive nanoribbons for interconnects in future 2D integrated circuits via n-type modulation doping. This misfit dislocation-driven growth can be applied to different combinations of 2D monolayers with lattice mismatch, paving the way to a wide range of 2D quantum-well superlattices with controllable band alignment and nanoscale width. |
2017 |
Wang, Song Ling; Luo, Xin; Zhou, Xiong; Zhu, Ye; Chi, Xiao; Chen, Wei; Wu, Kai; Liu, Zheng; Quek, Su Ying; Xu, Guo Qin Fabrication and Properties of a Free-Standing Two-Dimensional Titania Journal Article JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 139 (43), pp. 15414-15419, 2017, ISSN: 0002-7863. @article{ISI:000414506400024, title = {Fabrication and Properties of a Free-Standing Two-Dimensional Titania}, author = {Song Ling Wang and Xin Luo and Xiong Zhou and Ye Zhu and Xiao Chi and Wei Chen and Kai Wu and Zheng Liu and Su Ying Quek and Guo Qin Xu}, doi = {10.1021/jacs.7b08229}, times_cited = {0}, issn = {0002-7863}, year = {2017}, date = {2017-11-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {139}, number = {43}, pages = {15414-15419}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {The synthesis of free-standing two-dimensional titania (2-D TiO2) with a reduced band gap presents complex challenges to synthetic chemists. Here, we report a free-standing 2-D TiO2 sheet synthesized via a one-step solvothermal methodology, with a measured optical onset at similar to 1.84 eV. Using first-principles calculations in Combination with experiment, we propose that the as-formed 2-D TiO2 sheets are layers of the lepidocrocite TiO2 structure, but with large nonuniform Strains consistent with its crumpled morphology. These strains cause a significant change in the quasiparticle band structure and optical absorption spectra, resulting in large absorption in the visible-light region. This narrow band gap 2-D TiO2 can catalyze the formation of singlet oxygen and the degradation of dye pollutants with low-energy photons of solar fight. Our work demonstrates that lattice strains intrinsic to 2-D materials, especially its crumpled, free-standing forms, can result in new and useful properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The synthesis of free-standing two-dimensional titania (2-D TiO2) with a reduced band gap presents complex challenges to synthetic chemists. Here, we report a free-standing 2-D TiO2 sheet synthesized via a one-step solvothermal methodology, with a measured optical onset at similar to 1.84 eV. Using first-principles calculations in Combination with experiment, we propose that the as-formed 2-D TiO2 sheets are layers of the lepidocrocite TiO2 structure, but with large nonuniform Strains consistent with its crumpled morphology. These strains cause a significant change in the quasiparticle band structure and optical absorption spectra, resulting in large absorption in the visible-light region. This narrow band gap 2-D TiO2 can catalyze the formation of singlet oxygen and the degradation of dye pollutants with low-energy photons of solar fight. Our work demonstrates that lattice strains intrinsic to 2-D materials, especially its crumpled, free-standing forms, can result in new and useful properties. |
Belopolski, Ilya; Yu, Peng; Sanchez, Daniel S; Ishida, Yukiaki; Chang, Tay-Rong; Zhang, Songtian S; Xu, Su-Yang; Zheng, Hao; Chang, Guoqing; Bian, Guang; Jeng, Horng-Tay; Kondo, Takeshi; Lin, Hsin; Liu, Zheng; Shin, Shik; Hasan, Zahid M Signatures of a time-reversal symmetric Weyl semimetal with only four Weyl points Journal Article NATURE COMMUNICATIONS, 8 , 2017, ISSN: 2041-1723. @article{ISI:000412999700010, title = {Signatures of a time-reversal symmetric Weyl semimetal with only four Weyl points}, author = {Ilya Belopolski and Peng Yu and Daniel S Sanchez and Yukiaki Ishida and Tay-Rong Chang and Songtian S Zhang and Su-Yang Xu and Hao Zheng and Guoqing Chang and Guang Bian and Horng-Tay Jeng and Takeshi Kondo and Hsin Lin and Zheng Liu and Shik Shin and Zahid M Hasan}, doi = {10.1038/s41467-017-00938-1}, times_cited = {0}, issn = {2041-1723}, year = {2017}, date = {2017-10-16}, journal = {NATURE COMMUNICATIONS}, volume = {8}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {Through intense research on Weyl semimetals during the past few years, we have come to appreciate that typical Weyl semimetals host many Weyl points. Nonetheless, the minimum nonzero number of Weyl points allowed in a time-reversal invariant Weyl semimetal is four. Realizing such a system is of fundamental interest and may simplify transport experiments. Recently, it was predicted that TaIrTe4 realizes a minimal Weyl semimetal. However, the Weyl points and Fermi arcs live entirely above the Fermi level, making them inaccessible to conventional angle-resolved photoemission spectroscopy (ARPES). Here, we use pumpprobe ARPES to directly access the band structure above the Fermi level in TaIrTe4. We observe signatures of Weyl points and topological Fermi arcs. Combined with ab initio calculation, our results show that TaIrTe4 is a Weyl semimetal with the minimum number of four Weyl points. Our work provides a simpler platform for accessing exotic transport phenomena arising in Weyl semimetals.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Through intense research on Weyl semimetals during the past few years, we have come to appreciate that typical Weyl semimetals host many Weyl points. Nonetheless, the minimum nonzero number of Weyl points allowed in a time-reversal invariant Weyl semimetal is four. Realizing such a system is of fundamental interest and may simplify transport experiments. Recently, it was predicted that TaIrTe4 realizes a minimal Weyl semimetal. However, the Weyl points and Fermi arcs live entirely above the Fermi level, making them inaccessible to conventional angle-resolved photoemission spectroscopy (ARPES). Here, we use pumpprobe ARPES to directly access the band structure above the Fermi level in TaIrTe4. We observe signatures of Weyl points and topological Fermi arcs. Combined with ab initio calculation, our results show that TaIrTe4 is a Weyl semimetal with the minimum number of four Weyl points. Our work provides a simpler platform for accessing exotic transport phenomena arising in Weyl semimetals. |
Kenry, ; Geldert, Alisha; Lai, Zhuangchai; Huang, Ying; Yu, Peng; Tan, Chaoliang; Liu, Zheng; Zhang, Hua; Lim, Chwee Teck Single-Layer Ternary Chalcogenide Nanosheet as a Fluorescence-Based "Capture-Release" Biomolecular Nanosensor Journal Article SMALL, 13 (5), 2017, ISSN: 1613-6810. @article{ISI:000397009300013, title = {Single-Layer Ternary Chalcogenide Nanosheet as a Fluorescence-Based "Capture-Release" Biomolecular Nanosensor}, author = {Kenry and Alisha Geldert and Zhuangchai Lai and Ying Huang and Peng Yu and Chaoliang Tan and Zheng Liu and Hua Zhang and Chwee Teck Lim}, doi = {10.1002/smll.201601925}, times_cited = {0}, issn = {1613-6810}, year = {2017}, date = {2017-02-03}, journal = {SMALL}, volume = {13}, number = {5}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {The novel application of two-dimensional (2D) single-layer ternary chalcogenide nanosheets as "capture-release" fluorescence-based biomolecular nanosensors is demonstrated. Fluorescently labeled biomolecular probe is first captured by the ultrathin Ta2NiS5 nanosheets and then released upon adding analyte containing a target biomolecule due to the higher probe-target affinity. Here, the authors use a nucleic acid probe for the model target biomolecule Plasmodium lactate dehydrogenase, which is an important malarial biomarker. The ultrathin Ta2NiS5 nanosheet serves as a highly efficient fluorescence quencher and the nanosensor developed from the nanosheet is highly sensitive and specific toward the target biomolecule. Apart from the specificity toward the target biomolecule in homogeneous solutions, the developed nanosensor is capable of detecting and differentiating the target in heterogeneous solutions consisting of either a mixture of biomolecules or serum, with exceptional specificity. The simplicity of the " capture-release" method, by eliminating the need for preincubation of the probe with the test sample, may facilitate further development of portable and rapid biosensors. The authors anticipate that this ternary chalcogenide nanosheet-based biomolecular nanosensor will be useful for the rapid detection and differentiation of a wide range of chemical and biological species.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The novel application of two-dimensional (2D) single-layer ternary chalcogenide nanosheets as "capture-release" fluorescence-based biomolecular nanosensors is demonstrated. Fluorescently labeled biomolecular probe is first captured by the ultrathin Ta2NiS5 nanosheets and then released upon adding analyte containing a target biomolecule due to the higher probe-target affinity. Here, the authors use a nucleic acid probe for the model target biomolecule Plasmodium lactate dehydrogenase, which is an important malarial biomarker. The ultrathin Ta2NiS5 nanosheet serves as a highly efficient fluorescence quencher and the nanosensor developed from the nanosheet is highly sensitive and specific toward the target biomolecule. Apart from the specificity toward the target biomolecule in homogeneous solutions, the developed nanosensor is capable of detecting and differentiating the target in heterogeneous solutions consisting of either a mixture of biomolecules or serum, with exceptional specificity. The simplicity of the " capture-release" method, by eliminating the need for preincubation of the probe with the test sample, may facilitate further development of portable and rapid biosensors. The authors anticipate that this ternary chalcogenide nanosheet-based biomolecular nanosensor will be useful for the rapid detection and differentiation of a wide range of chemical and biological species. |
Sun, Bo; Gu, Xiaokun; Zeng, Qingsheng; Huang, Xi; Yan, Yuexiang; Liu, Zheng; Yang, Ronggui; Koh, Yee Kan Temperature Dependence of Anisotropic Thermal-Conductivity Tensor of Bulk Black Phosphorus Journal Article ADVANCED MATERIALS, 29 (3), 2017, ISSN: 0935-9648. @article{ISI:000392729800005, title = {Temperature Dependence of Anisotropic Thermal-Conductivity Tensor of Bulk Black Phosphorus}, author = {Bo Sun and Xiaokun Gu and Qingsheng Zeng and Xi Huang and Yuexiang Yan and Zheng Liu and Ronggui Yang and Yee Kan Koh}, doi = {10.1002/adma.201603297}, times_cited = {0}, issn = {0935-9648}, year = {2017}, date = {2017-01-18}, journal = {ADVANCED MATERIALS}, volume = {29}, number = {3}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {The anisotropic thermal-conductivity tensor of bulk black phosphorus (BP) for 80 <= T <= 300 K is reported. Despite the anisotropy, phonons are predominantly scattered by Umklapp processes in all the crystallographic orientations. It is also found that the phonon mean-free-paths of BP are rather long (up to 1 mu m) in the through-plane direction.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The anisotropic thermal-conductivity tensor of bulk black phosphorus (BP) for 80 <= T <= 300 K is reported. Despite the anisotropy, phonons are predominantly scattered by Umklapp processes in all the crystallographic orientations. It is also found that the phonon mean-free-paths of BP are rather long (up to 1 mu m) in the through-plane direction. |
Zhou, Jiadong; Liu, Fucai; Lin, Junhao; Huang, Xiangwei; Xia, Juan; Zhang, Bowei; Zeng, Qingsheng; Wang, Hong; Zhu, Chao; Niu, Lin; Wang, Xuewen; Fu, Wei; Yu, Peng; Chang, Tay-Rong; Hsu, Chuang-Han; Wu, Di; Jeng, Horng-Tay; Huang, Yizhong; Lin, Hsin; Shen, Zexiang; Yang, Changli; Lu, Li; Suenaga, Kazu; Zhou, Wu; Pantelides, Sokrates T; Liu, Guangtong; Liu, Zheng Large-Area and High-Quality 2D Transition Metal Telluride Journal Article ADVANCED MATERIALS, 29 (3), 2017, ISSN: 0935-9648. @article{ISI:000392729800008, title = {Large-Area and High-Quality 2D Transition Metal Telluride}, author = {Jiadong Zhou and Fucai Liu and Junhao Lin and Xiangwei Huang and Juan Xia and Bowei Zhang and Qingsheng Zeng and Hong Wang and Chao Zhu and Lin Niu and Xuewen Wang and Wei Fu and Peng Yu and Tay-Rong Chang and Chuang-Han Hsu and Di Wu and Horng-Tay Jeng and Yizhong Huang and Hsin Lin and Zexiang Shen and Changli Yang and Li Lu and Kazu Suenaga and Wu Zhou and Sokrates T Pantelides and Guangtong Liu and Zheng Liu}, doi = {10.1002/adma.201603471}, times_cited = {0}, issn = {0935-9648}, year = {2017}, date = {2017-01-18}, journal = {ADVANCED MATERIALS}, volume = {29}, number = {3}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Large-area and high-quality 2D transition metal tellurides are synthesized by the chemical vapor deposition method. The as-grown WTe2 maintains two different stacking sequences in the bilayer, where the atomic structure of the stacking boundary is revealed by scanning transmission electron microscopy. The low-temperature transport measurements reveal a novel semimetal-to-insulator transition in WTe2 layers and an enhanced superconductivity in few-layer MoTe2.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Large-area and high-quality 2D transition metal tellurides are synthesized by the chemical vapor deposition method. The as-grown WTe2 maintains two different stacking sequences in the bilayer, where the atomic structure of the stacking boundary is revealed by scanning transmission electron microscopy. The low-temperature transport measurements reveal a novel semimetal-to-insulator transition in WTe2 layers and an enhanced superconductivity in few-layer MoTe2. |