25 Dec 04:33
Nanoscale, 2019, 11,19923-19932
DOI: 10.1039/C9NR04726C, Paper
Xue-Liang Zhu, Peng-Fei Liu, Junrong Zhang, Ping Zhang, Wu-Xing Zhou, Guofeng Xie, Bao-Tian Wang
Monolayer SnP3 is a novel two-dimensional (2D) semiconductor material with high carrier mobility and large optical absorption coefficient, implying its potential applications in the photovoltaic and thermoelectric (TE) fields.
The content of this RSS Feed (c) The Royal Society of Chemistry
25 Dec 04:33
by Xun Zhang,
Jizhou Jiang,
Abdulsalam Aji Suleiman,
Bao Jin,
Xiaozong Hu,
Xing Zhou,
Tianyou Zhai
For the first time, 2D ultrathin Te flakes (5 nm) are successfully realized by hydrogen‐assisted chemical vapor deposition method. The density functional theory calculations and experiments confirm that two volatile intermediates increase the vapor pressure of the source and promote the reaction. Impressively, the Te‐flake‐based phototransistor shows giant gate‐dependent photoresponse.
Abstract
Tellurium (Te), as an elementary material, has attracted intense attention due to its potentially novel properties. However, it is still a great challenge to realize high‐quality 2D Te due to its helical chain structure. Here, ultrathin Te flakes (5 nm) are synthesized via hydrogen‐assisted chemical vapor deposition method. The density functional theory calculations and experiments confirm the growth mechanism, which can be ascribed to the formation of volatile intermediates increasing vapor pressure of the source and promoting the reaction. Impressively, the Te flake‐based transistor shows high on/off ratio ≈104, ultralow off‐state current ≈8 × 10−13 A, as well as a negligible hysteresis due to reducing thermally activated defects at 80 K. Moreover, Te‐flake‐based phototransistor demonstrates giant gate‐dependent photoresponse: when gate voltage varies from −70 to 70 V, I
on/I
off is increased by ≈40‐fold. The hydrogen‐assisted strategy may provide a new approach for synthesizing other high quality 2D elementary materials.
24 Dec 02:34
by Shi‐Jun Liang,
Bin Cheng,
Xinyi Cui,
Feng Miao
The diverse properties of van der Waals heterostructures open unprecedented opportunities for various types of device applications inaccessible in conventional heterostructure materials. Research progress of vertical heterostructure device applications in vertical transistors, infrared photodetectors, and spintronic devices is reviewed, together with a discussion on the challenges and opportunities in the future development of multifunctional devices.
Abstract
The discovery of two‐dimensional (2D) materials with unique electronic, superior optoelectronic, or intrinsic magnetic order has triggered worldwide interest in the fields of material science, condensed matter physics, and device physics. Vertically stacking 2D materials with distinct electronic and optical as well as magnetic properties enables the creation of a large variety of van der Waals heterostructures. The diverse properties of the vertical heterostructures open unprecedented opportunities for various kinds of device applications, e.g., vertical field‐effect transistors, ultrasensitive infrared photodetectors, spin‐filtering devices, and so on, which are inaccessible in conventional material heterostructures. Here, the current status of vertical heterostructure device applications in vertical transistors, infrared photodetectors, and spintronic memory/transistors is reviewed. The relevant challenges for achieving high‐performance devices are presented. An outlook into the future development of vertical heterostructure devices with integrated electronic and optoelectronic as well as spintronic functionalities is also provided.
24 Dec 02:33
by Nicholas R. Glavin,
Rahul Rao,
Vikas Varshney,
Elisabeth Bianco,
Amey Apte,
Ajit Roy,
Emilie Ringe,
Pulickel M. Ajayan
Elemental 2D materials are some of the more exciting nanomaterials of interest due to their unique and tailorable properties. Recent progress in these exciting materials relative to their potential impact in applications including electronics, optoelectronics, and energy systems is presented.
Abstract
As elemental main group materials (i.e., silicon and germanium) have dominated the field of modern electronics, their monolayer 2D analogues have shown great promise for next‐generation electronic materials as well as potential game‐changing properties for optoelectronics, energy, and beyond. These atomically thin materials composed of single atomic variants of group III through group VI elements on the periodic table have already demonstrated exciting properties such as near‐room‐temperature topological insulation in bismuthene, extremely high electron mobilities in phosphorene and silicone, and substantial Li‐ion storage capability in borophene. Isolation of these materials within the postgraphene era began with silicene in 2010 and quickly progressed to the experimental identification or theoretical prediction of 15 of the 18 main group elements existing as solids at standard pressure and temperatures. This review first focuses on the significance of defects/functionalization, discussion of different allotropes, and overarching structure–property relationships of 2D main group elemental materials. Then, a complete review of emerging applications in electronics, sensing, spintronics, plasmonics, photodetectors, ultrafast lasers, batteries, supercapacitors, and thermoelectrics is presented by application type, including detailed descriptions of how the material properties may be tailored toward each specific application.
05 Nov 08:29
by Yichao Zhang and David J. Flannigan*
Nano Letters
DOI: 10.1021/acs.nanolett.9b03596
05 Nov 08:28
by Weinan Xu†?, Tengfei Li‡, Zhao Qin§?, Qi Huang†, Hui Gao??, Kibum Kang??, Jiwoong Park?, Markus J. Buehler§, Jacob B. Khurgin‡, and David H. Gracias*†#
Nano Letters
DOI: 10.1021/acs.nanolett.9b03107
28 Oct 01:00
by Jiuk Jang†‡?¶, Hyobeom Kim†‡?¶, Sangyoon Ji†‡?, Ha Jun Kim§, Min Soo Kang?, Tae Soo Kim?, Jong-eun Won‡?, Jae-Hyun Lee‡?, Jinwoo Cheon*‡?#, Kibum Kang*?, Won Bin Im*§, and Jang-Ung Park*†‡?
Nano Letters
DOI: 10.1021/acs.nanolett.9b02978
28 Oct 00:57
by Eugenio Coronado
Nature Reviews Materials, Published online: 24 October 2019; doi:10.1038/s41578-019-0146-8
This Review discusses the expansion of the field of molecular magnetism from the chemical design and physical study of single-molecule magnets and multifunctional magnetic materials towards physics- and nanotechnology-driven areas, in particular molecular spintronics, quantum technologies, metal–organic frameworks and 2D materials.
28 Oct 00:56
by Szostak, R., Silva, J. C., Turren-Cruz, S.- H., Soares, M. M., Freitas, R. O., Hagfeldt, A., Tolentino, H. C. N., Nogueira, A. F.
Lead-based organic-inorganic hybrid perovskite (OIHP) solar cells can attain efficiencies over 20%. However, the impact of ion mobility and/or organic depletion, structural changes, and segregation under operating conditions urge for decisive and more accurate investigations. Hence, the development of analytical tools for accessing the grain-to-grain OIHP chemistry is of great relevance. Here, we used synchrotron infrared nanospectroscopy (nano-FTIR) to map individual nanograins in OIHP films. Our results reveal a spatial heterogeneity of the vibrational activity associated to the nanoscale chemical diversity of isolated grains. It was possible to map the chemistry of individual grains in CsFAMA [Cs0.05FA0.79MA0.16Pb(I0.83Br0.17)3] and FAMA [FA0.83MA0.17Pb(I0.83Br0.17)3] films, with information on their local composition. Nanograins with stronger nano-FTIR activity in CsFAMA and FAMA films can be assigned to PbI2 and hexagonal polytype phases, respectively. The analysis herein can be extended to any OIHP films where organic cation depletion/accumulation can be used as a chemical label to study composition.
24 Oct 02:53
by Anne C. Nickel†, Andrea Scotti*†, Judith E. Houston‡§, Thiago Ito?, Je´ro^me Crassous†, Jan Skov Pedersen?, and Walter Richtering*†#
Nano Letters
DOI: 10.1021/acs.nanolett.9b03507
24 Oct 02:52
by Qiong Liu†, Haifei Zhan†, Huaiyong Zhu†, Hongwei Liu‡, Ziqi Sun†, John Bell†, Arixin Bo†*, and Yuantong Gu†*
Nano Letters
DOI: 10.1021/acs.nanolett.9b02685
24 Oct 02:52
by Ankur Sharma†, Ahmed Khan†, Yi Zhu, Robert Halbich, Wendi Ma, Yilin Tang, Bowen Wang, and Yuerui Lu*
Nano Letters
DOI: 10.1021/acs.nanolett.9b02943
19 Oct 08:23
by Arkamita Bandyopadhyay†, Nathan C. Frey†, Deep Jariwala†‡, and Vivek B. Shenoy*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b02801
14 Oct 02:48
by Rikhia Ghosh†, Vahid Satarifard†, Andrea Grafmu¨ller, and Reinhard Lipowsky*
Nano Letters
DOI: 10.1021/acs.nanolett.9b02646
14 Oct 02:38
by Liu, X., Hersam, M. C.
Integration of dissimilar two-dimensional (2D) materials is essential for nanoelectronic applications. Compared to vertical stacking, covalent lateral stitching requires bottom-up synthesis, resulting in rare realizations of 2D lateral heterostructures. Because of its polymorphism and diverse bonding geometries, borophene is a promising candidate for 2D heterostructures, although suitable synthesis conditions have not yet been demonstrated. Here, we report lateral and vertical integration of borophene with graphene. Topographic and spatially resolved spectroscopic measurements reveal nearly atomically sharp lateral interfaces despite imperfect crystallographic lattice and symmetry matching. In addition, boron intercalation under graphene results in rotationally commensurate vertical heterostructures. The rich bonding configurations of boron suggest that borophene can be integrated into a diverse range of 2D heterostructures.
14 Oct 02:37
by He, Z., Han, Z., Yuan, J., Sinyukov, A. M., Eleuch, H., Niu, C., Zhang, Z., Lou, J., Hu, J., Voronine, D. V., Scully, M. O.
Monitoring and controlling the neutral and charged excitons (trions) in two-dimensional (2D) materials are essential for the development of high-performance devices. However, nanoscale control is challenging because of diffraction-limited spatial resolution of conventional far-field techniques. Here, we extend the classical tip-enhanced photoluminescence based on tip-substrate nanocavity to quantum regime and demonstrate controlled nano-optical imaging, namely, tip-enhanced quantum plasmonics. In addition to improving the spatial resolution, we use the scanning probe to control the optoelectronic response of monolayer WS2 by varying the neutral/charged exciton ratio via charge tunneling in Au-Ag picocavity. We observe trion "hot spots" generated by varying the picometer-scale probe-sample distance and show the effects of weak and strong coupling, which depend on the spatial location. Our experimental results are in agreement with simulations and open an unprecedented view of a new range of quantum plasmonic phenomena with 2D materials that will help to design new quantum optoelectronic devices.
08 Oct 01:39
by Rau¨l Perea-Causi´n*†, Samuel Brem†, Roberto Rosati†, Roland Jago†, Marvin Kulig‡, Jonas D. Ziegler‡, Jonas Zipfel‡, Alexey Chernikov‡, and Ermin Malic†
Nano Letters
DOI: 10.1021/acs.nanolett.9b02948
08 Oct 01:39
by Xin Yin†, Yizhan Wang†, Ryan Jacobs†, Yeqi Shi, Izabela Szlufarska, Dane Morgan, and Xudong Wang*
Nano Letters
DOI: 10.1021/acs.nanolett.9b02581
08 Oct 01:39
by Di Pang†, Mohamed Alhabeb‡, Xinpeng Mu†, Yohan Dall’Agnese*§, Yury Gogotsi*†‡, and Yu Gao*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b03147
08 Oct 01:37
by Aron W. Cummings*†§, Simon M.-M. Dubois‡§, Jean-Christophe Charlier‡, and Stephan Roche†¶
Nano Letters
DOI: 10.1021/acs.nanolett.9b03112
08 Oct 01:37
by Teruyoshi Matsuda†, Kyohei Takada†, Kohsuke Yano†, Rikuo Tsutsumi†, Kohei Yoshikawa†, Satoshi Shimomura†, Yumiko Shimizu‡, Kazuki Nagashima*§, Takeshi Yanagida§, and Fumitaro Ishikawa*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b02932
08 Oct 01:37
by Dongying Wang†, Shi Che†, Guixin Cao†, Rui Lyu‡, Kenji Watanabe§, Takashi Taniguchi§, Chun Ning Lau†, and Marc Bockrath*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b02445
08 Oct 01:36
by Jinjiang Zhang†, Ruifeng Zhou*‡§, Hiro Minamimoto‡, Satoshi Yasuda‡, and Kei Murakoshi*‡
Nano Letters
DOI: 10.1021/acs.nanolett.9b02947
08 Oct 01:36
by Anthony Aiello†, Yuanpeng Wu†, Ayush Pandey†, Ping Wang†, Woncheol Lee†, Dylan Bayerl‡, Nocona Sanders‡, Zihao Deng‡, Jiseok Gim‡, Kai Sun‡, Robert Hovden‡, Emmanouil Kioupakis‡, Zetian Mi†, and Pallab Bhattacharya*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b02847
08 Oct 01:35
by Xiangye Liu†?, Baichang Li‡, Xufan Li§, Avetik R. Harutyunyan§, James Hone*‡, and Daniel V. Esposito*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b03337
08 Oct 01:33
by Li, J., Cho, J., Ding, J., Charalambous, H., Xue, S., Wang, H., Phuah, X. L., Jian, J., Wang, X., Ophus, C., Tsakalakos, T., Garcia, R. E., Mukherjee, A. K., Bernstein, N., Hellberg, C. S., Wang, H., Zhang, X.
Ceramic materials have been widely used for structural applications. However, most ceramics have rather limited plasticity at low temperatures and fracture well before the onset of plastic yielding. The brittle nature of ceramics arises from the lack of dislocation activity and the need for high stress to nucleate dislocations. Here, we have investigated the deformability of TiO2 prepared by a flash-sintering technique. Our in situ studies show that the flash-sintered TiO2 can be compressed to ~10% strain under room temperature without noticeable crack formation. The room temperature plasticity in flash-sintered TiO2 is attributed to the formation of nanoscale stacking faults and nanotwins, which may be assisted by the high-density preexisting defects and oxygen vacancies introduced by the flash-sintering process. Distinct deformation behaviors have been observed in flash-sintered TiO2 deformed at different testing temperatures, ranging from room temperature to 600°C. Potential mechanisms that may render ductile ceramic materials are discussed.
08 Oct 01:32
by Godin, A. G., Setaro, A., Gandil, M., Haag, R., Adeli, M., Reich, S., Cognet, L.
The design of single-molecule photoswitchable emitters was the first milestone toward the advent of single-molecule localization microscopy, setting a new paradigm in the field of optical imaging. Several photoswitchable emitters have been developed, but they all fluoresce in the visible or far-red ranges, missing the desirable near-infrared window where biological tissues are most transparent. Moreover, photocontrol of individual emitters in the near-infrared would be highly desirable for elementary optical molecular switches or information storage elements since most communication data transfer protocols are established in this spectral range. Here, we introduce a type of hybrid nanomaterials consisting of single-wall carbon nanotubes covalently functionalized with photoswitching molecules that are used to control the intrinsic luminescence of the single nanotubes in the near-infrared (beyond 1 μm). Through the control of photoswitching, we demonstrate super-localization imaging of nanotubes unresolved by diffraction-limited microscopy.
08 Oct 01:32
by Zhang, Z., Mannix, A. J., Liu, X., Hu, Z., Guisinger, N. P., Hersam, M. C., Yakobson, B. I.
Two-dimensional boron, borophene, was realized in recent experiments but still lacks an adequate growth theory for guiding its controlled synthesis. Combining ab initio calculations and experimental characterization, we study edges and growth kinetics of borophene on Ag(111). In equilibrium, the borophene edges are distinctly reconstructed with exceptionally low energies, in contrast to those of other two-dimensional materials. Away from equilibrium, sequential docking of boron feeding species to the reconstructed edges tends to extend the given lattice out of numerous polymorphic structures. Furthermore, each edge can grow via multiple energy pathways of atomic row assembly due to variable boron-boron coordination. These pathways reveal different degrees of anisotropic growth kinetics, shaping borophene into diverse elongated hexagonal islands in agreement with experimental observations in terms of morphology as well as edge orientation and periodicity. These results further suggest that ultrathin borophene ribbons can be grown at low temperature and low boron chemical potential.
08 Oct 01:32
by Ziatdinov, M., Dyck, O., Li, X., Sumpter, B. G., Jesse, S., Vasudevan, R. K., Kalinin, S. V.
The presence and configurations of defects are primary components determining materials functionality. Their population and distribution are often nonergodic and dependent on synthesis history, and therefore rarely amenable to direct theoretical prediction. Here, dynamic electron beam–induced transformations in Si deposited on a graphene monolayer are used to create libraries of possible Si and carbon vacancy defects. Deep learning networks are developed for automated image analysis and recognition of the defects, creating a library of (meta) stable defect configurations. Density functional theory is used to estimate atomically resolved scanning tunneling microscopy (STM) signatures of the classified defects from the created library, allowing identification of several defect types across imaging platforms. This approach allows automatic creation of defect libraries in solids, exploring the metastable configurations always present in real materials, and correlative studies with other atomically resolved techniques, providing comprehensive insight into defect functionalities.
08 Oct 01:32
by Codecido, E., Wang, Q., Koester, R., Che, S., Tian, H., Lv, R., Tran, S., Watanabe, K., Taniguchi, T., Zhang, F., Bockrath, M., Lau, C. N.
The emergence of flat bands and correlated behaviors in "magic angle" twisted bilayer graphene (tBLG) has sparked tremendous interest, though its many aspects are under intense debate. Here we report observation of both superconductivity and the Mott-like insulating state in a tBLG device with a twist angle of ~0.93°, which is smaller than the magic angle by 15%. At an electron concentration of ±5 electrons/moiré unit cell, we observe a narrow resistance peak with an activation energy gap ~0.1 meV. This indicates additional correlated insulating state, and is consistent with theory predicting a high-energy flat band. At doping of ±12 electrons/moiré unit cell we observe resistance peaks arising from the Dirac points in the spectrum. Our results reveal that the "magic" range of tBLG is in fact larger than what is previously expected, and provide a wealth of new information to help decipher the strongly correlated phenomena observed in tBLG.