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Li J, Yang R, Higashitarumizu N, Dai S, Wu J, Javey A, Grigoropoulos CP. Transient Nanoscopy of Exciton Dynamics in 2D Transition Metal Dichalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311568. [PMID: 38588584 DOI: 10.1002/adma.202311568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/18/2024] [Indexed: 04/10/2024]
Abstract
The electronic and optical properties of 2D transition metal dichalcogenides are dominated by strong excitonic resonances. Exciton dynamics plays a critical role in the functionality and performance of many miniaturized 2D optoelectronic devices; however, the measurement of nanoscale excitonic behaviors remains challenging. Here, a near-field transient nanoscopy is reported to probe exciton dynamics beyond the diffraction limit. Exciton recombination and exciton-exciton annihilation processes in monolayer and bilayer MoS2 are studied as the proof-of-concept demonstration. Moreover, with the capability to access local sites, intriguing exciton dynamics near the monolayer-bilayer interface and at the MoS2 nano-wrinkles are resolved. Such nanoscale resolution highlights the potential of this transient nanoscopy for fundamental investigation of exciton physics and further optimization of functional devices.
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Affiliation(s)
- Jingang Li
- Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, CA, 94720, USA
| | - Rundi Yang
- Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, CA, 94720, USA
| | - Naoki Higashitarumizu
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Siyuan Dai
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Junqiao Wu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Ali Javey
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Costas P Grigoropoulos
- Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, CA, 94720, USA
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2
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Jo K, Stevens CE, Choi B, El-Khoury PZ, Hendrickson JR, Jariwala D. Core/Shell-Like Localized Emission at Atomically Thin Semiconductor-Au Interface. NANO LETTERS 2024. [PMID: 38593418 DOI: 10.1021/acs.nanolett.3c03790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Localized emission in atomically thin semiconductors has sparked significant interest as single-photon sources. Despite comprehensive studies into the correlation between localized strain and exciton emission, the impacts of charge transfer on nanobubble emission remains elusive. Here, we report the observation of core/shell-like localized emission from monolayer WSe2 nanobubbles at room temperature through near-field studies. By altering the electronic junction between monolayer WSe2 and the Au substrate, one can effectively adjust the semiconductor to metal junction from a Schottky to an Ohmic junction. Through concurrent analysis of topography, potential, tip-enhanced photoluminescence, and a piezo response force microscope, we attribute the core/shell-like emissions to strong piezoelectric potential aided by induced polarity at the WSe2-Au Schottky interface which results in spatial confinement of the excitons. Our findings present a new approach for manipulating charge confinement and engineering localized emission within atomically thin semiconductor nanobubbles. These insights hold implications for advancing the nano and quantum photonics with low-dimensional semiconductors.
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Affiliation(s)
- Kiyoung Jo
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Christopher E Stevens
- KBR Inc., Beavercreek, Ohio 45431, United States
- Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB Ohio 45433, United States
| | - Bongjun Choi
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patrick Z El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Joshua R Hendrickson
- Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB Ohio 45433, United States
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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3
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Yanev ES, Darlington TP, Ladyzhets SA, Strasbourg MC, Trovatello C, Liu S, Rhodes DA, Hall K, Sinha A, Borys NJ, Hone JC, Schuck PJ. Programmable nanowrinkle-induced room-temperature exciton localization in monolayer WSe 2. Nat Commun 2024; 15:1543. [PMID: 38378789 PMCID: PMC10879107 DOI: 10.1038/s41467-024-45936-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 02/08/2024] [Indexed: 02/22/2024] Open
Abstract
Localized states in two-dimensional (2D) transition metal dichalcogenides (TMDCs) have been the subject of intense study, driven by potential applications in quantum information science. Despite the rapidly growing knowledge surrounding these emitters, their microscopic nature is still not fully understood, limiting their production and application. Motivated by this challenge, and by recent theoretical and experimental evidence showing that nanowrinkles generate strain-localized room-temperature emitters, we demonstrate a method to intentionally induce wrinkles with collections of stressors, showing that long-range wrinkle direction and position are controllable with patterned array design. Nano-photoluminescence (nano-PL) imaging combined with detailed strain modeling based on measured wrinkle topography establishes a correlation between wrinkle properties, particularly shear strain, and localized exciton emission. Beyond the array-induced wrinkles, nano-PL spatial maps further reveal that the strain environment around individual stressors is heterogeneous due to the presence of fine wrinkles that are less deterministic. At cryogenic temperatures, antibunched emission is observed, confirming that the nanocone-induced strain is sufficiently large for the formation of quantum emitters. At 300 K, detailed nanoscale hyperspectral images uncover a wide range of low-energy emission peaks originating from the fine wrinkles, and show that the states can be tightly confined to regions <10 nm, even in ambient conditions. These results establish a promising potential route towards realizing room temperature quantum emission in 2D TMDC systems.
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Affiliation(s)
- Emanuil S Yanev
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Thomas P Darlington
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Sophia A Ladyzhets
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | | | - Chiara Trovatello
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Song Liu
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Daniel A Rhodes
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Kobi Hall
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Aditya Sinha
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Nicholas J Borys
- Department of Physics, Montana State University, Bozeman, MT, USA.
| | - James C Hone
- Department of Mechanical Engineering, Columbia University, New York, NY, USA.
| | - P James Schuck
- Department of Mechanical Engineering, Columbia University, New York, NY, USA.
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4
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Wang J, He L, Zhang Y, Nong H, Li S, Wu Q, Tan J, Liu B. Locally Strained 2D Materials: Preparation, Properties, and Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2314145. [PMID: 38339886 DOI: 10.1002/adma.202314145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/28/2024] [Indexed: 02/12/2024]
Abstract
2D materials are promising for strain engineering due to their atomic thickness and exceptional mechanical properties. In particular, non-uniform and localized strain can be induced in 2D materials by generating out-of-plane deformations, resulting in novel phenomena and properties, as witnessed in recent years. Therefore, the locally strained 2D materials are of great value for both fundamental studies and practical applications. This review discusses techniques for introducing local strains to 2D materials, and their feasibility, advantages, and challenges. Then, the unique effects and properties that arise from local strain are explored. The representative applications based on locally strained 2D materials are illustrated, including memristor, single photon emitter, and photodetector. Finally, concluding remarks on the challenges and opportunities in the emerging field of locally strained 2D materials are provided.
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Affiliation(s)
- Jingwei Wang
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Liqiong He
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Yunhao Zhang
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Huiyu Nong
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Shengnan Li
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Qinke Wu
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Junyang Tan
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Bilu Liu
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
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Huang JT, Bai B, Han YX, Feng PY, Wang XJ, Li XZ, Huang GY, Sun HB. Super-Resolution Exciton Imaging of Nanobubbles in 2D Semiconductors with Near-Field Nanophotoluminescence Microscopy. ACS NANO 2024; 18:272-280. [PMID: 38096138 DOI: 10.1021/acsnano.3c06102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Two-dimensional (2D) semiconductors, such as transition metal dichalcogenides, have emerged as important candidate materials for next-generation chip-scale optoelectronic devices with the development of large-scale production techniques, such as chemical vapor deposition (CVD). However, 2D materials need to be transferred to other target substrates after growth, during which various micro- and nanoscale defects, such as nanobubbles, are inevitably generated. These nanodefects not only influence the uniformity of 2D semiconductors but also may significantly alter the local optoelectronic properties of the composed devices. Hence, super-resolution discrimination and characterization of nanodefects are highly demanded. Here, we report a near-field nanophotoluminescence (nano-PL) microscope that can quickly screen nanobubbles and investigate their impact on local excitonic properties of 2D semiconductors by directly visualize the PL emission distribution with a very high spatial resolution of ∼10 nm, far below the optical diffraction limit, and a high speed of 10 ms/point under ambient conditions. By using nano-PL microscopy to map the exciton and trion emission intensity distributions in transferred CVD-grown monolayer tungsten disulfide (1L-WS2) flakes, it is found that the PL intensity decreases by 13.4% as the height of the nanobubble increases by every nanometer, which is mainly caused by the suppression of trion emission due to the strong doping effect from the substrate. In addition to the nanobubbles, other types of nanodefects, such as cracks, stacks, and grain boundaries, can also be characterized. The nano-PL method is proven to be a powerful tool for the nondestructive quality inspection of nanodefects as well as the super-resolution exploration of local optoelectronic properties of 2D materials.
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Affiliation(s)
- Jia-Tai Huang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Benfeng Bai
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Yu-Xiao Han
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Peng-Yi Feng
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Xiao-Jie Wang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Xiao-Ze Li
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Guan-Yao Huang
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Beijing Key Laboratory of CO2 Utilization and Reduction Technology, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Hong-Bo Sun
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
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Xie T, Ma X, Guo Y, Yuan G, Liao J, Ma N, Huang C. A graphene/Janus B 2P 6 heterostructure with a controllable Schottky barrier via interlayer distance and electric field. Phys Chem Chem Phys 2023; 25:31238-31248. [PMID: 37955158 DOI: 10.1039/d3cp03732k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Lowering the Schottky barrier at the metal-semiconductor interface remains a stern challenge in the field of field-effect transistors. Herein, an in-depth investigation was conducted to explore the formation mechanism of the Schottky barrier via interlayer distance and external electric field, utilizing the first-principles approach. Attributed to the vertical asymmetric structure of B2P6, ohmic contact forms at the interface of a graphene/B2P6(001) heterostructure, and an n-type Schottky contact with a Schottky barrier of 0.51 eV forms at the interface of a graphene/B2P6(001̄) heterostructure. Furthermore, the Schottky barrier height and the contact type can be changed by adjusting the interlayer spacing or applying an electric field along the Z direction. A high carrier concentration of 4.65 × 1013 cm-2 is obtained in the graphene/B2P6(001) heterostructure when an external electric field of 0.05 V Å-1 is applied. Verifiably, alterations in the energy band structure are attributed to the redistribution of charges at the interface. The new findings indicate that GR/B2P6 heterostructures are a key candidate for next-generation Schottky field-effect transistor development.
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Affiliation(s)
- Tian Xie
- School of Science, Hubei University of Technology, Wuhan 430068, China.
| | - Xinguo Ma
- School of Science, Hubei University of Technology, Wuhan 430068, China.
- 111 Research Center, Hubei University of Technology, Wuhan 430068, China.
| | - Youyou Guo
- School of Science, Hubei University of Technology, Wuhan 430068, China.
| | - Gang Yuan
- School of Science, Hubei University of Technology, Wuhan 430068, China.
| | - JiaJun Liao
- School of Science, Hubei University of Technology, Wuhan 430068, China.
| | - Nan Ma
- Key Laboratory of Inorganic Functional Materials and Devices, Chinese Academy of Sciences, Shanghai 201899, China
| | - Chuyun Huang
- 111 Research Center, Hubei University of Technology, Wuhan 430068, China.
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7
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Zhou J, Thomas JC, Barre E, Barnard ES, Raja A, Cabrini S, Munechika K, Schwartzberg A, Weber-Bargioni A. Near-Field Coupling with a Nanoimprinted Probe for Dark Exciton Nanoimaging in Monolayer WSe 2. NANO LETTERS 2023. [PMID: 37262350 DOI: 10.1021/acs.nanolett.3c00621] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Tip-enhanced photoluminescence (TRPL) is a powerful technique for spatially and spectrally probing local optical properties of 2-dimensional (2D) materials that are modulated by the local heterogeneities, revealing inaccessible dark states due to bright state overlap in conventional far-field microscopy at room temperature. While scattering-type near-field probes have shown the potential to selectively enhance and reveal dark exciton emission, their technical complexity and sensitivity can pose challenges under certain experimental conditions. Here, we present a highly reproducible and easy-to-fabricate near-field probe based on nanoimprint lithography and fiber-optic excitation and collection. The novel near-field measurement configuration provides an ∼3 orders of magnitude out-of-plane Purcell enhancement, diffraction-limited excitation spot, and subdiffraction hyperspectral imaging resolution (below 50 nm) of dark exciton emission. The effectiveness of this high spatial XD mapping technique was then demonstrated through reproducible hyperspectral mapping of oxidized sites and bubble areas.
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Affiliation(s)
- Junze Zhou
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - John C Thomas
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Elyse Barre
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Edward S Barnard
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Archana Raja
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Stefano Cabrini
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Keiko Munechika
- HighRI Optics, Inc. 5401 Broadway Ter 304, Oakland, California 94618, United States
| | - Adam Schwartzberg
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Alexander Weber-Bargioni
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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Liang K, Bi L, Zhu Q, Zhou H, Li S. Ultrafast Dynamics Revealed with Time-Resolved Scanning Tunneling Microscopy: A Review. ACS APPLIED OPTICAL MATERIALS 2023; 1:924-938. [PMID: 37260467 PMCID: PMC10227725 DOI: 10.1021/acsaom.2c00169] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/23/2023] [Indexed: 06/02/2023]
Abstract
A scanning tunneling microscope (STM) capable of performing pump-probe spectroscopy integrates unmatched atomic-scale resolution with high temporal resolution. In recent years, the union of electronic, terahertz, or visible/near-infrared pulses with STM has contributed to our understanding of the atomic-scale processes that happen between milliseconds and attoseconds. This time-resolved STM (TR-STM) technique is evolving into an unparalleled approach for exploring the ultrafast nuclear, electronic, or spin dynamics of molecules, low-dimensional structures, and material surfaces. Here, we review the recent advancements in TR-STM; survey its application in measuring the dynamics of three distinct systems, nucleus, electron, and spin; and report the studies on these transient processes in a series of materials. Besides the discussion on state-of-the-art techniques, we also highlight several emerging research topics about the ultrafast processes in nanoscale objects where we anticipate that the TR-STM can help broaden our knowledge.
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Affiliation(s)
- Kangkai Liang
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Liya Bi
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Qingyi Zhu
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
| | - Hao Zhou
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Shaowei Li
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
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