Xingxing Zhang

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01 Dec 03:08

[ASAP] Direct Measurement of Folding Angle and Strain Vector in Atomically Thin WS2 Using Second-Harmonic Generation

by Ahmed Raza Khan, Boqing Liu, Tieyu Lü, Linglong Zhang, Ankur Sharma, Yi Zhu, Wendi Ma, and Yuerui Lu

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ACS Nano
DOI: 10.1021/acsnano.0c06901
01 Dec 03:08

[ASAP] 2H-MoS2 on Mo2CTx MXene Nanohybrid for Efficient and Durable Electrocatalytic Hydrogen Evolution

by Kang Rui Garrick Lim, Albertus D. Handoko, Luke R. Johnson, Xing Meng, Ming Lin, Gomathy Sandhya Subramanian, Babak Anasori, Yury Gogotsi, Aleksandra Vojvodic, and Zhi Wei Seh

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ACS Nano
DOI: 10.1021/acsnano.0c08671
01 Dec 03:07

[ASAP] Photophysics and Electronic Structure of Lateral Graphene/MoS2 and Metal/MoS2 Junctions

by Shruti Subramanian, Quinn T. Campbell, Simon K. Moser, Jonas Kiemle, Philipp Zimmermann, Paul Seifert, Florian Sigger, Deeksha Sharma⊙, Hala Al-Sadeg, Michael Labella, III◊, Dacen Waters◨, Randall M. Feenstra◨, Roland J. Koch, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Ismaila Dabo, Alexander W. Holleitner, Thomas E. Beechem◓, Ursula Wurstbauer⧫, and Joshua A. Robinson◪⊕

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ACS Nano
DOI: 10.1021/acsnano.0c02527
01 Dec 03:07

[ASAP] Inclined Ultrathin Bi2O2Se Films: A Building Block for Functional van der Waals Heterostructures

by Chengyun Hong, Ye Tao, Anmin Nie, Minhao Zhang, Nan Wang, Ruiping Li, Junquan Huang, Yongqing Huang, Xiaomin Ren, Yingchun Cheng, and Xiaolong Liu

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ACS Nano
DOI: 10.1021/acsnano.0c05300
01 Dec 02:58

[ASAP] Growth Kinetics and Atomistic Mechanisms of Native Oxidation of ZrSxSe2–x and MoS2 Crystals

by Seong Soon Jo, Akshay Singh, Liqiu Yang, Subodh C. Tiwari, Sungwook Hong, Aravind Krishnamoorthy, Maria Gabriela Sales, Sean M. Oliver, Joshua Fox, Randal L. Cavalero, David W. Snyder, Patrick M. Vora, Stephen J. McDonnell, Priya Vashishta, Rajiv K. Kalia, Aiichiro Nakano, and R. Jaramillo

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Nano Letters
DOI: 10.1021/acs.nanolett.0c03263
01 Dec 02:50

Van der Waals Epitaxial Growth of Mosaic‐Like 2D Platinum Ditelluride Layers for Room‐Temperature Mid‐Infrared Photodetection up to 10.6 µm

by Longhui Zeng, Di Wu, Jiansheng Jie, Xiaoyan Ren, Xin Hu, Shu Ping Lau, Yang Chai, Yuen Hong Tsang
Van der Waals Epitaxial Growth of Mosaic‐Like 2D Platinum Ditelluride Layers for Room‐Temperature Mid‐Infrared Photodetection up to 10.6 µm

Van der Waals epitaxial growth of wafer‐scale mosaic‐like 2D PtTe2 layer is achieved for highly sensitive MIR photodetection. A photodetector based on a PtTe2/Si Schottky junction is capable of sensing ultrabroadband light of up to 10.6 µm with a high specific detectivity. The photodetector arrays also display an excellent room‐temperature MIR imaging capability.


Abstract

Mid‐infrared (MIR) photodetection, covering diverse molecular vibrational regions and atmospheric transmission windows, is vital to civil and military purposes. Versatile use of MIR photodetectors is commonly dominated by HgCdTe alloys, InSb, and quantum superlattices, which are limited by strict operation demands, high‐cost, and environmental toxicity. Despite the rapid advances of black phosphorus (BP)‐based MIR photodetectors, these are subject to poor stability and large‐area integration difficulty. Here, the van der Waals (vdW) epitaxial growth of a wafer‐scale 2D platinum ditelluride (PtTe2) layer is reported via a simple tellurium‐vapor transformation approach. The 2D PtTe2 layer possesses a unique mosaic‐like crystal structure consisting of single‐crystal domains with highly preferential [001] orientation along the normal direction, reducing the influence of interface defects and ensuring efficient out‐of‐plane carrier transportation. This characteristic, combined with the wide absorption of PtTe2 and well‐designed vertical device architecture, makes the PtTe2/Si Schottky junction photodetector capable of sensing ultra‐broadband light of up to 10.6 µm with a high specific detectivity. Also, the photodetector exhibits an excellent room‐temperature infrared‐imaging capability. This approach provides a new design concept for high‐performance, room‐temperature MIR photodetection based on 2D layered materials.

01 Dec 02:47

Room‐Temperature Synthesis of 2D Janus Crystals and their Heterostructures

by Dipesh B. Trivedi, Guven Turgut, Ying Qin, Mohammed Y. Sayyad, Debarati Hajra, Madeleine Howell, Lei Liu, Sijie Yang, Naim Hossain Patoary, Han Li, Marko M. Petrić, Moritz Meyer, Malte Kremser, Matteo Barbone, Giancarlo Soavi, Andreas V. Stier, Kai Müller, Shize Yang, Ivan Sanchez Esqueda, Houlong Zhuang, Jonathan J. Finley, Sefaattin Tongay
Room‐Temperature Synthesis of 2D Janus Crystals and their Heterostructures

Janus crystals represent an exciting class of 2D materials with different atomic species on their upper and lower facets. Theories predict that this broken symmetry leads to a wealth of novel properties. A room‐temperature technique for the synthesis of a variety of Janus monolayers and their lateral and vertical heterostructures with high structural and optical quality is reported.


Abstract

Janus crystals represent an exciting class of 2D materials with different atomic species on their upper and lower facets. Theories have predicted that this symmetry breaking induces an electric field and leads to a wealth of novel properties, such as large Rashba spin–orbit coupling and formation of strongly correlated electronic states. Monolayer MoSSe Janus crystals have been synthesized by two methods, via controlled sulfurization of monolayer MoSe2 and via plasma stripping followed thermal annealing of MoS2. However, the high processing temperatures prevent growth of other Janus materials and their heterostructures. Here, a room‐temperature technique for the synthesis of a variety of Janus monolayers with high structural and optical quality is reported. This process involves low‐energy reactive radical precursors, which enables selective removal and replacement of the uppermost chalcogen layer, thus transforming classical transition metal dichalcogenides into a Janus structure. The resulting materials show clear mixed character for their excitonic transitions, and more importantly, the presented room‐temperature method enables the demonstration of first vertical and lateral heterojunctions of 2D Janus TMDs. The results present significant and pioneering advances in the synthesis of new classes of 2D materials, and pave the way for the creation of heterostructures from 2D Janus layers.

11 Nov 11:30

[ASAP] Mechanisms and Applications of Steady-State Photoluminescence Spectroscopy in Two-Dimensional Transition-Metal Dichalcogenides

by Mike Tebyetekerwa, Jian Zhang, Zhen Xu, Thien N. Truong, Zongyou Yin, Yuerui Lu, Seeram Ramakrishna, Daniel Macdonald, and Hieu T. Nguyen

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ACS Nano
DOI: 10.1021/acsnano.0c08668
11 Nov 11:28

[ASAP] Robust Spin Interconnect with Isotropic Spin Dynamics in Chemical Vapor Deposited Graphene Layers and Boundaries

by Dmitrii Khokhriakov, Bogdan Karpiak, Anamul Md. Hoque, Bing Zhao, Subir Parui, and Saroj P. Dash

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ACS Nano
DOI: 10.1021/acsnano.0c07163
11 Nov 11:28

[ASAP] Atomic and Electronic Structure of a Multidomain GeTe Crystal

by Alexander S. Frolov, Jaime Sánchez-Barriga, Carolien Callaert, Joke Hadermann, Alexander V. Fedorov, Dmitry Yu. Usachov, Alexander N. Chaika□, Brian C. Walls△, Kuanysh Zhussupbekov△, Igor V. Shvets△, Matthias Muntwiler▽, Matteo Amati⬡, Luca Gregoratti⬡, Andrei Yu. Varykhalov, Oliver Rader, and Lada V. Yashina

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ACS Nano
DOI: 10.1021/acsnano.0c05851
11 Nov 11:28

[ASAP] Measurement of Exciton and Trion Energies in Multistacked hBN/WS2 Coupled Quantum Wells for Resonant Tunneling Diodes

by Myoung-Jae Lee, David H. Seo, Sung Min Kwon, Dohun Kim, Youngwook Kim, Won Seok Yun, Jung-Hwa Cha, Hyeon-Kyo Song, Shinbuhm Lee, MinKyung Jung, Hyeon-Jun Lee, June-Seo Kim, Jae-Sang Heo, Sunae Seo, and Sung Kyu Park

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ACS Nano
DOI: 10.1021/acsnano.0c08133
11 Nov 11:28

[ASAP] A Robust Strategy for Engineering Fe7S8/C Hybrid Nanocages Reinforced by Defect-Rich MoS2 Nanosheets for Superior Potassium-Ion Storage

by Wenda Li, Dezhu Wang, Zhijiang Gong, Zhengmao Yin, Xiaosong Guo, Jing Liu, Changming Mao, Zhonghua Zhang, and Guicun Li

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ACS Nano
DOI: 10.1021/acsnano.0c07733
11 Nov 11:27

[ASAP] Magnetic Direct-Write Skyrmion Nanolithography

by A. V. Ogneva, A. G. Kolesnikova, Yong Jin Kimb, In Ho Chab, A. V. Sadovnikovcd, S. A. Nikitovcd, I. V. Soldatovej, A. Talapatraf, J. Mohantyf, M. Mruczkiewiczgk, Y. Geh, N. Kerberh, F. Dittrichh, P. Virnauh, M. Kläuih, Young Keun Kimb, and A. S. Samardakai

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ACS Nano
DOI: 10.1021/acsnano.0c04748
11 Nov 11:27

[ASAP] Microscopic Detection Analysis of Single Molecules in MoS2 Membrane Nanopores

by Mingye Xiong, Michael Graf, Nagendra Athreya, Aleksandra Radenovic, and Jean-Pierre Leburton

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ACS Nano
DOI: 10.1021/acsnano.0c08382
11 Nov 11:20

[ASAP] Highly Efficient Multiple Exciton Generation and Harvesting in Few-Layer Black Phosphorus and Heterostructure

by Qiaohui Zhou, Hongzhi Zhou, Weijian Tao, Yizhen Zheng, Yuzhong Chen, and Haiming Zhu

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Nano Letters
DOI: 10.1021/acs.nanolett.0c03328
11 Nov 11:20

[ASAP] Interfacial Polarons in van der Waals Heterojunction of Monolayer SnSe2 on SrTiO3 (001)

by Yahui Mao, Xiaochuan Ma, Daoxiong Wu, Chen Lin, Huan Shan, Xiaojun Wu, Jin Zhao, Aidi Zhao, and Bing Wang

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Nano Letters
DOI: 10.1021/acs.nanolett.0c02741
11 Nov 11:19

[ASAP] Switchable, Tunable, and Directable Exciton Funneling in Periodically Wrinkled WS2

by Jubok Lee, Seok Joon Yun, Changwon Seo, Kiwon Cho, Tae Soo Kim, Gwang Hwi An, Kibum Kang, Hyun Seok Lee, and Jeongyong Kim

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Nano Letters
DOI: 10.1021/acs.nanolett.0c02619
11 Nov 11:17

[ASAP] Electro-Ionic Control of Surface Plasmons in Graphene-Layered Heterostructures

by Jian Yi Pae, Rohit Medwal, Radhika V. Nair, Avinash Chaurasiya, Marco Battiato, Rajdeep Singh Rawat, and Murukeshan Vadakke Matham

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Nano Letters
DOI: 10.1021/acs.nanolett.0c03471
11 Nov 11:17

[ASAP] Tailoring Single- and Double-Sided Fluorination of Bilayer Graphene via Substrate Interactions

by Jangyup Son, Huije Ryu, Junyoung Kwon, Siyuan Huang, Jaehyung Yu, Jingwei Xu△, Kenji Watanabe, Takashi Taniguchi, Eunji Ji, Sol Lee, Yongjun Shin, Jong Hun Kim, Kwanpyo Kim, Arend M. van der Zande, and Gwan-Hyoung Lee

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Nano Letters
DOI: 10.1021/acs.nanolett.0c03237
11 Nov 11:16

[ASAP] Ultrafast Optical Modulation of Harmonic Generation in Two-Dimensional Materials

by Yang Cheng, Hao Hong, Hui Zhao, Chunchun Wu, Yu Pan, Can Liu, Yonggang Zuo, Zhihong Zhang, Jin Xie, Jinhuan Wang, Dapeng Yu□, Yu Ye, Sheng Meng, and Kaihui Liu

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Nano Letters
DOI: 10.1021/acs.nanolett.0c02972
11 Nov 11:15

[ASAP] Layer Edge States Stabilized by Internal Electric Fields in Two-Dimensional Hybrid Perovskites

by Jisook Hong, David Prendergast, and Liang Z. Tan

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Nano Letters
DOI: 10.1021/acs.nanolett.0c03468
11 Nov 11:15

[ASAP] Super-Nernstian pH Sensor Based on Anomalous Charge Transfer Doping of Defect-Engineered Graphene

by Su-Ho Jung, Young-Min Seo, Taejun Gu, Wonseok Jang, Seog-Gyun Kang, Yuhwan Hyeon, Sang-Hwa Hyun, Jae-Hyun Lee, and Dongmok Whang

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Nano Letters
DOI: 10.1021/acs.nanolett.0c02259
11 Nov 11:15

[ASAP] Frustrated Layered Self-Assembly Induced Superlattice from Two-Dimensional Nanosheets

by Huanjun Lu&, Xiaoyan Zhang&, Tsuneaki Sakurai, Xiaohong Li, Yingfeng Tu, Jun Guo, Shu Seki, Christopher Y. Li, Goran Ungar, and Stephen Z. D. Cheng%

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Nano Letters
DOI: 10.1021/acs.nanolett.0c03352
11 Nov 11:13

Wafer‐Scale Fabrication of 2D β‐In2Se3 Photodetectors

by Marcel S. Claro, Justyna Grzonka, Nicoleta Nicoara, Paulo J. Ferreira, Sascha Sadewasser
Wafer‐Scale Fabrication of 2D β‐In2Se3 Photodetectors

The epitaxial growth of high‐quality and single‐phase β‐In2Se3 by molecular beam epitaxy (MBE) on a 2 in. wafer scale is demonstrated down to two quintuple layers (QL). The wafer‐scale fabrication of photodetectors with five QL is realized using the MBE and other standard semiconductor processing methods, which allows easy integration into the current semiconductor technology.


Abstract

2D materials are considered the future of electronics and photonics, stimulated by their remarkable performance. Among the 2D materials family, β‐In2Se3 shows good mobility, excellent photoresponsivity, and exotic ferroelectricity, making it suitable for a wide variety of applications. To date, most reported devices from 2D materials in general, and β‐In2Se3 in specific, rely on cumbersome fabrication methods using mechanical exfoliation and transfer of layers onto other substrates. However, for a successful adoption of 2D materials in industry, reliable and reproducible large‐area growth of 2D materials is required. Here, the wafer‐scale epitaxial growth of 2D β‐In2Se3 on c‐sapphire using molecular beam epitaxy is demonstrated. Excellent materials quality of thick (90 nm) and very thin films, down to two quintuple layers (2 nm) is confirmed. Furthermore, the fabrication of hundreds of photodetector devices on a 2 in. wafer, using five quintuple layers of β‐In2Se3, is demonstrated. They are sensitive to near‐infrared light up to 898 nm wavelength and show a response time of ≈7 ms, which is faster than any result previously reported for β‐In2Se3 photodetectors. The devices are produced using photolithography and other standard semiconductor processing methods, which allows easy integration into the current Si technology.

11 Nov 11:10

Discovering Electron‐Transfer‐Driven Changes in Chemical Bonding in Lead Chalcogenides (PbX, where X = Te, Se, S, O)

by Stefan Maier, Simon Steinberg, Yudong Cheng, Carl‐Friedrich Schön, Mathias Schumacher, Riccardo Mazzarello, Pavlo Golub, Ryky Nelson, Oana Cojocaru‐Mirédin, Jean‐Yves Raty, Matthias Wuttig
Discovering Electron‐Transfer‐Driven Changes in Chemical Bonding in Lead Chalcogenides (PbX, where X = Te, Se, S, O)

Systematic changes of chemical bonding in lead chalcogenides (PbX, where X = Te, Se, S, O) are studied to comprehend their properties. The exploration reveals an electron‐transfer‐driven transition from metavalent bonding in PbX (X = Te, Se, S) to iono‐covalent bonding in β‐PbO. The insights gained from this study highlight the technological relevance of the concept of metavalent bonding and its potential for materials design.


Abstract

Understanding the nature of chemical bonding in solids is crucial to comprehend the physical and chemical properties of a given compound. To explore changes in chemical bonding in lead chalcogenides (PbX, where X = Te, Se, S, O), a combination of property‐, bond‐breaking‐, and quantum‐mechanical bonding descriptors are applied. The outcome of the explorations reveals an electron‐transfer‐driven transition from metavalent bonding in PbX (X = Te, Se, S) to iono‐covalent bonding in β‐PbO. Metavalent bonding is characterized by adjacent atoms being held together by sharing about a single electron (ES ≈ 1) and small electron transfer (ET). The transition from metavalent to iono‐covalent bonding manifests itself in clear changes in these quantum‐mechanical descriptors (ES and ET), as well as in property‐based descriptors (i.e., Born effective charge (Z*), dielectric function ε(ω), effective coordination number (ECoN), and mode‐specific Grüneisen parameter (γTO)), and in bond‐breaking descriptors. Metavalent bonding collapses if significant charge localization occurs at the ion cores (ET) and/or in the interatomic region (ES). Predominantly changing the degree of electron transfer opens possibilities to tailor material properties such as the chemical bond (Z*) and electronic (ε∞) polarizability, optical bandgap, and optical interband transitions characterized by ε2(ω). Hence, the insights gained from this study highlight the technological relevance of the concept of metavalent bonding and its potential for materials design.

11 Nov 11:08

Visualizing Tailored Spin Phenomena in a Reduced‐Dimensional Topological Superlattice

by Rui Sun, Shijia Yang, Xu Yang, A. Kumar, Eric Vetter, Wenhua Xue, Yan Li, Na Li, Yang Li, Shihao Zhang, Binghui Ge, Xiang‐qun Zhang, Wei He, Alexander F. Kemper, Dali Sun, Zhao‐hua Cheng
Visualizing Tailored Spin Phenomena in a Reduced‐Dimensional Topological Superlattice

Topological states with tailored spin phenomena are realized in a reduced‐dimensional superlattice structure, (□/Bi2Se3)‐(Bi2/Bi2Se3) N or Bi2/Bi2Se3‐(Bi2/Bi2Se3) N (N is the repeating unit) by controlling different terminations via molecular beam epitaxy. This work suggests a promising route of engineering topological superlattices for efficient spin–charge transducers and long‐lived spin transport spintronic applications.


Abstract

Emergent topological insulators (TIs) and their design are in high demand for manipulating and transmitting spin information toward ultralow‐power‐consumption spintronic applications. Here, distinct topological states with tailored spin properties can be achieved in a single reduced‐dimensional TI‐superlattice, (Bi2/Bi2Se3)‐(Bi2/Bi2Se3) N or (□/Bi2Se3)‐(Bi2/Bi2Se3) N (N is the repeating unit, □ represents an empty layer) by controlling the termination via molecular beam epitaxy. The Bi2‐terminated superlattice exhibits a single Dirac cone with a spin momentum splitting ≈0.5 Å−1, producing a pronounced inverse Edelstein effect with a coherence length up to 1.26 nm. In contrast, the Bi2Se3‐terminated superlattice is identified as a dual TI protected by coexisting time reversal and mirror symmetries, showing an unexpectedly long spin lifetime up to 1 ns. The work elucidates the key role of dimensionality and dual topological phases in selecting desired spin properties, suggesting a promise route for engineering topological superlattices for high‐performance TI‐spintronic devices.

11 Nov 11:07

2D Transition Metal Carbides (MXenes): Applications as an Electrically Conducting Material

by Faisal Shahzad, Aamir Iqbal, Hyerim Kim, Chong Min Koo
2D Transition Metal Carbides (MXenes): Applications as an Electrically Conducting Material

The excellent metallic conductivity of MXenes has elevated them to the forefront of a wide range of applications. The performance of highly conductive MXenes is comparable to that of conductive metals, and superior to many carbon‐based nanomaterials for electromagnetic shielding, conducting electrodes, sensors, and thermal heaters. A brief overview of the mentioned application areas is presented.


Abstract

Since their discovery in 2011, 2D transition metal carbides, nitrides, and carbonitrides, known as MXenes, have attracted considerable global research interest owing to their outstanding electrical conductivity coupled with light weight, flexibility, transparency, surface chemistry tunability, and easy solution processability. Here, the promising abilities of 2D MXenes, from both experimental and theoretical perspectives, for designing conductive materials for a range of applications, including electromagnetic interference shielding, flexible optoelectronics, sensors, and thermal heaters, are presented.

02 Nov 02:10

Tunable Ferromagnetism and Thermally Induced Spin Flip in Vanadium‐Doped Tungsten Diselenide Monolayers at Room Temperature

by Yen Thi Hai Pham, Mingzu Liu, Valery Ortiz Jimenez, Zhuohang Yu, Vijaysankar Kalappattil, Fu Zhang, Ke Wang, Teague Williams, Mauricio Terrones, Manh‐Huong Phan
Tunable Ferromagnetism and Thermally Induced Spin Flip in Vanadium‐Doped Tungsten Diselenide Monolayers at Room Temperature

Strong and tunable room‐temperature ferromagnetism is achieved in vanadium‐doped tungsten diselenide monolayers using a reproducible and atmospheric‐pressure film sulfidation growth method. As the vanadium concentration increases, the saturation magnetization increases, which is optimal at ≈4 at% vanadium—the highest doping level ever achieved for V‐doped WSe2 monolayers. A novel thermally induced spin flipping effect is also discovered in these monolayers.


Abstract

The outstanding optoelectronic and valleytronic properties of transition metal dichalcogenides (TMDs) have triggered intense research efforts by the scientific community. An alternative to induce long‐range ferromagnetism (FM) in TMDs is by introducing magnetic dopants to form a dilute magnetic semiconductor. Enhancing ferromagnetism in these semiconductors not only represents a key step toward modern TMD‐based spintronics, but also enables exploration of new and exciting dimensionality‐driven magnetic phenomena. To this end, tunable ferromagnetism at room temperature and a thermally induced spin flip (TISF) in monolayers of V‐doped WSe2 are shown. As vanadium concentration increases, the saturation magnetization increases, which is optimal at ≈4 at% vanadium; the highest doping level ever achieved for V‐doped WSe2 monolayers. The TISF occurs at ≈175 K and becomes more pronounced upon increasing the temperature toward room temperature. The TISF can be manipulated by changing the vanadium concentration. The TISF is attributed to the magnetic‐field‐ and temperature‐dependent flipping of the nearest W‐site magnetic moments that are antiferromagnetically coupled to the V magnetic moments in the ground state. This is fully supported by a recent spin‐polarized density functional theory study. The findings pave the way for the development of novel spintronic and valleytronic nanodevices and stimulate further research.

02 Nov 02:02

Supramolecular Chiral 2D Materials and Emerging Functions

by Bowen Shen, Yongju Kim, Myongsoo Lee
Supramolecular Chiral 2D Materials and Emerging Functions

Chiral materials are widely applied in various fields, providing stereospecific conditions and environments. Recent progress in the construction of 2D chiral materials and their emerging functions is reviewed, focusing on construction strategies, enantiomeric separation, asymmetric catalysis, and chiroptical effects. A perspective is given to construct single‐layered chiral sheets with uniform‐sized chiral pores that can be used as chiral nanoreactors.


Abstract

Chiral materials are widely applied in various fields such as enantiomeric separation, asymmetric catalysis, and chiroptical effects, providing stereospecific conditions and environments. Supramolecular concepts to create the chiral materials can provide an insight for emerging chiro‐optical properties due to their well‐defined scaffolds and the precise functionalization of the surfaces or skeletons. Among the various supramolecular chiral structures, 2D chiral sheet structures are particularly interesting materials because of their extremely high surface area coupled with many unique chemical and physical properties, thereby offering potential for the next generation of functional materials for optically active systems and optoelectronic devices. Nevertheless, relatively limited examples for 2D chiral materials exhibiting specific functionality have been reported because incorporation of molecular chirality into 2D architectures is difficult at the present stage. Here, a brief overview of the recent advances is provided on the construction of chiral supramolecular 2D materials and their functions. The design principles toward 2D chirality and their potential applications are also discussed.

02 Nov 02:00

Heterogeneous Electronic and Photonic Devices Based on Monolayer Ternary Telluride Core/Shell Structures

by Kai Xu, Ankit Sharma, Junzhe Kang, Xiaoqiao Hu, Zheng Hao, Wenjuan Zhu
Heterogeneous Electronic and Photonic Devices Based on Monolayer Ternary Telluride Core/Shell Structures

Monolayer ternary telluride core/shell WSe2−2 x Te2 x /WSe2−2 y Te2 y (x > y) structures are synthesized using a one‐step chemical vapor deposition process with rapid cooling. The lateral gradient of the bandgap across the monolayer heterostructure allows for the fabrication of heterogeneous transistors and photodetectors. As a result, heterogeneous transistors demonstrate a unidirectional conduction and strong photovoltaic effect.


Abstract

Device engineering based on the tunable electronic properties of ternary transition metal dichalcogenides has recently gained widespread research interest. In this work, monolayer ternary telluride core/shell structures are synthesized using a one‐step chemical vapor deposition process with rapid cooling. The core region is the tellurium‐rich WSe2−2 x Te2 x alloy, while the shell is the tellurium‐poor WSe2−2 y Te2 y alloy. The bandgap of the material is ≈1.45 eV in the core region and ≈1.57 eV in the shell region. The lateral gradient of the bandgap across the monolayer heterostructure allows for the fabrication of heterogeneous transistors and photodetectors. The difference in work function between the core and shell regions leads to a built‐in electric field at the heterojunction. As a result, heterogeneous transistors demonstrate a unidirectional conduction and strong photovoltaic effect. The bandgap gradient and high mobility of the ternary telluride core/shell structures provide a unique material platform for novel electronic and photonic devices.