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Peña Román RJ, Auad Y, Grasso L, Padilha LA, Alvarez F, Barcelos ID, Kociak M, Zagonel LF. Design and implementation of a device based on an off-axis parabolic mirror to perform luminescence experiments in a scanning tunneling microscope. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:043704. [PMID: 35489916 DOI: 10.1063/5.0078423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
We present the design, implementation, and illustrative results of a light collection/injection strategy based on an off-axis parabolic mirror collector for a low-temperature Scanning Tunneling Microscope (STM). This device allows us to perform STM induced Light Emission (STM-LE) and Cathodoluminescence (STM-CL) experiments and in situ Photoluminescence (PL) and Raman spectroscopy as complementary techniques. Considering the Étendue conservation and using an off-axis parabolic mirror, it is possible to design a light collection and injection system that displays 72% of collection efficiency (considering the hemisphere above the sample surface) while maintaining high spectral resolution and minimizing signal loss. The performance of the STM is tested by atomically resolved images and scanning tunneling spectroscopy results on standard sample surfaces. The capabilities of our system are demonstrated by performing STM-LE on metallic surfaces and two-dimensional semiconducting samples, observing both plasmonic and excitonic emissions. In addition, we carried out in situ PL measurements on semiconducting monolayers and quantum dots and in situ Raman on graphite and hexagonal boron nitride (h-BN) samples. Additionally, STM-CL and PL were obtained on monolayer h-BN gathering luminescence spectra that are typically associated with intragap states related to carbon defects. The results show that the flexible and efficient light injection and collection device based on an off-axis parabolic mirror is a powerful tool to study several types of nanostructures with multiple spectroscopic techniques in correlation with their morphology at the atomic scale and electronic structure.
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Affiliation(s)
- Ricardo Javier Peña Román
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Yves Auad
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Lucas Grasso
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Lazaro A Padilha
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Fernando Alvarez
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
| | - Ingrid David Barcelos
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-970 Campinas, SP, Brazil
| | - Mathieu Kociak
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Luiz Fernando Zagonel
- "Gleb Wataghin" Institute of Physics, University of Campinas-UNICAMP, 13083-859 Campinas, SP, Brazil
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2
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Wang Y, Xue N, Li R, Wu T, Li N, Hou S, Wang Y. Construction and Properties of Sierpiński Triangular Fractals on Surfaces. Chemphyschem 2019; 20:2262-2270. [PMID: 31291053 DOI: 10.1002/cphc.201900258] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/24/2019] [Indexed: 11/07/2022]
Abstract
Fractal structures are of fundamental importance in science, engineering, mathematics, and aesthetics. Construction of molecular fractals on surfaces can help to understand the formation mechanism of fractals and a series of achievements have been acquired in the preparation of molecular fractals. This review focuses on Sierpiński triangles (STs), representatives of various prototypical fractals, on surfaces. They are investigated by Monte Carlo simulations and ultra-high vacuum scanning tunneling microscopy. STs are bonded through halogen bonds, hydrogen bonds, metal-organic coordination bonds and covalent bonds. The coexistence of and competition between fractals and crystals are realized for a hydrogen-bonded system. Electronic properties of two types of STs are summarized.
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Affiliation(s)
- Yifan Wang
- School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing, 100871, China
| | - Na Xue
- School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing, 100871, China
| | - Ruoning Li
- School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing, 100871, China
| | - Tianhao Wu
- School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing, 100871, China
| | - Na Li
- School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing, 100871, China
| | - Shimin Hou
- School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing, 100871, China
| | - Yongfeng Wang
- School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing, 100871, China
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Wu C, Zhang J, Tong X, Yu P, Xu JY, Wu J, Wang ZM, Lou J, Chueh YL. A Critical Review on Enhancement of Photocatalytic Hydrogen Production by Molybdenum Disulfide: From Growth to Interfacial Activities. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900578. [PMID: 31165564 DOI: 10.1002/smll.201900578] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/23/2019] [Indexed: 06/09/2023]
Abstract
Ultrathin 2D molybdenum disulfide (MoS2 ), which is the flagship of 2D transition-metal dichalcogenide nanomaterials, has drawn much attention in the last few years. 2D MoS2 has been banked as an alternative to platinum for highly active hydrogen evolution reaction because of its low cost, high surface-to-volume ratio, and abundant active sites. However, when MoS2 is used directly as a photocatalyst, contrary to public expectation, it still performs poorly due to lateral size, high recombination ratio of excitons, and low optical cross section. Besides, simply compositing MoS2 as a cocatalyst with other semiconductors cannot satisfy the practical application, which stimulates the pursual of a comprehensive insight into recent advances in synthesis, properties, and enhanced hydrogen production of MoS2 . Therefore, in this Review, emphasis is given to synthetic methods, phase transitions, tunable optical properties, and interfacial engineering of 2D MoS2 . Abundant ways of band edge tuning, structural modification, and phase transition are addressed, which can generate the neoteric photocatalytic systems. Finally, the main challenges and opportunities with respect to MoS2 being a cocatalyst and coherent light-matter interaction of MoS2 in photocatalytic systems are proposed.
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Affiliation(s)
- Cuo Wu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Jing Zhang
- Department of Materials Science and Nanoengineering, Rice University, Houston, TX, 77005, USA
| | - Xin Tong
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Peng Yu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Jing-Yin Xu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Jiang Wu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Zhiming M Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Jun Lou
- Department of Materials Science and Nanoengineering, Rice University, Houston, TX, 77005, USA
| | - Yu-Lun Chueh
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan, ROC
- Department of Physics, National Sun Yat-Sen University, Kaohsiung, 80424, Taiwan, ROC
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu, 30013, Taiwan, ROC
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Kastl C, Koch RJ, Chen CT, Eichhorn J, Ulstrup S, Bostwick A, Jozwiak C, Kuykendall TR, Borys NJ, Toma FM, Aloni S, Weber-Bargioni A, Rotenberg E, Schwartzberg AM. Effects of Defects on Band Structure and Excitons in WS 2 Revealed by Nanoscale Photoemission Spectroscopy. ACS NANO 2019; 13:1284-1291. [PMID: 30645100 DOI: 10.1021/acsnano.8b06574] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two-dimensional materials with engineered composition and structure will provide designer materials beyond conventional semiconductors. However, the potentials of defect engineering remain largely untapped, because it hinges on a precise understanding of electronic structure and excitonic properties, which are not yet predictable by theory alone. Here, we utilize correlative, nanoscale photoemission spectroscopy to visualize how local introduction of defects modifies electronic and excitonic properties of two-dimensional materials at the nanoscale. As a model system, we study chemical vapor deposition grown monolayer WS2, a prototypical, direct gap, two-dimensional semiconductor. By cross-correlating nanoscale angle-resolved photoemission spectroscopy, core level spectroscopy, and photoluminescence, we unravel how local variations in defect density influence electronic structure, lateral band alignment, and excitonic phenomena in synthetic WS2 monolayers.
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Affiliation(s)
- Christoph Kastl
- The Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Roland J Koch
- The Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Christopher T Chen
- The Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Johanna Eichhorn
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Søren Ulstrup
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO) , Aarhus University , 8000 Aarhus C, Denmark
| | - Aaron Bostwick
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Chris Jozwiak
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Tevye R Kuykendall
- The Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Nicholas J Borys
- Department of Physics , Montana State University , Bozeman , Montana 59717 , United States
| | - Francesca M Toma
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Shaul Aloni
- The Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Alexander Weber-Bargioni
- The Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Eli Rotenberg
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Adam M Schwartzberg
- The Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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5
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Hu C, Chen Q, Chen F, Gfroerer TH, Wanlass MW, Zhang Y. Overcoming diffusion-related limitations in semiconductor defect imaging with phonon-plasmon-coupled mode Raman scattering. LIGHT, SCIENCE & APPLICATIONS 2018; 7:23. [PMID: 30839595 PMCID: PMC6106988 DOI: 10.1038/s41377-018-0016-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/23/2018] [Accepted: 03/26/2018] [Indexed: 06/01/2023]
Abstract
Carrier diffusion is of paramount importance in many semiconductor devices, such as solar cells, photodetectors, and power electronics. Structural defects prevent such devices from reaching their full performance potential. Although a large carrier diffusion length indicates high material quality, it also implies increased carrier depletion by an individual extended defect (for instance, a dislocation) and obscures the spatial resolution of neighboring defects using optical techniques. For commonly utilized photoluminescence (PL) imaging, the spatial resolution is dictated by the diffusion length rather than by the laser spot size, no matter the spot is at or below the diffraction limit. Here, we show how Raman imaging of the LO phonon-plasmon-coupled mode can be used to recover the intrinsic spatial resolution of the optical system, and we demonstrate the effectiveness of the technique by imaging defects in GaAs with diffraction-limited optics, achieving a 10-fold improvement in resolution. Furthermore, by combining Raman and PL imaging, we can independently and simultaneously determine the spatial dependence of the electron density, hole density, radiative recombination rate, and non-radiative recombination rate near a dislocation-like defect, which has not been possible using other techniques.
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Affiliation(s)
- Changkui Hu
- University of North Carolina at Charlotte, Charlotte, NC 28223 USA
- Wuhan University of Technology, Wuhan, Hubei 430070 China
| | - Qiong Chen
- University of North Carolina at Charlotte, Charlotte, NC 28223 USA
| | - Fengxiang Chen
- University of North Carolina at Charlotte, Charlotte, NC 28223 USA
- Wuhan University of Technology, Wuhan, Hubei 430070 China
| | | | - M. W. Wanlass
- National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Yong Zhang
- University of North Carolina at Charlotte, Charlotte, NC 28223 USA
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A Review of Three-Dimensional Scanning Near-Field Optical Microscopy (3D-SNOM) and Its Applications in Nanoscale Light Management. APPLIED SCIENCES-BASEL 2017. [DOI: 10.3390/app7100973] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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7
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Kuhnke K, Große C, Merino P, Kern K. Atomic-Scale Imaging and Spectroscopy of Electroluminescence at Molecular Interfaces. Chem Rev 2017; 117:5174-5222. [DOI: 10.1021/acs.chemrev.6b00645] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Klaus Kuhnke
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
| | - Christoph Große
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
| | - Pablo Merino
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung, Stuttgart 70569, Germany
- Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
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8
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Gao R, Yan D. Layered host-guest long-afterglow ultrathin nanosheets: high-efficiency phosphorescence energy transfer at 2D confined interface. Chem Sci 2017; 8:590-599. [PMID: 28451206 PMCID: PMC5358535 DOI: 10.1039/c6sc03515a] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 09/02/2016] [Indexed: 12/20/2022] Open
Abstract
Tuning and optimizing the efficiency of light energy transfer play an important role in meeting modern challenges of minimizing energy loss and developing high-performance optoelectronic materials. However, attempts to fabricate systems giving highly efficient energy transfer between luminescent donor and acceptor have achieved limited success to date. Herein, we present a strategy towards phosphorescence energy transfer at a 2D orderly crystalline interface. We first show that new ultrathin nanosheet materials giving long-afterglow luminescence can be obtained by assembling aromatic guests into a layered double hydroxide host. Furthermore, we demonstrate that co-assembly of these long-lived energy donors with an energy acceptor in the same host generates an ordered arrangement of phosphorescent donor-acceptor pairs spatially confined within the 2D nanogallery, which affords energy transfer efficiency as high as 99.7%. Therefore, this work offers an alternative route to develop new types of long-afterglow nanohybrids and efficient light transfer systems with potential energy, illumination and sensor applications.
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Affiliation(s)
- Rui Gao
- State Key Laboratory of Chemical Resource Engineering , Beijing University of Chemical Technology , Beijing 100029 , P. R. China .
| | - Dongpeng Yan
- State Key Laboratory of Chemical Resource Engineering , Beijing University of Chemical Technology , Beijing 100029 , P. R. China .
- Beijing Key Laboratory of Energy Conversion and Storage Materials , College of Chemistry , Beijing Normal University , Beijing 100875 , P. R. China .
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Bogaert K, Liu S, Chesin J, Titow D, Gradečak S, Garaj S. Diffusion-Mediated Synthesis of MoS2/WS2 Lateral Heterostructures. NANO LETTERS 2016; 16:5129-5134. [PMID: 27438807 DOI: 10.1021/acs.nanolett.6b02057] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Controlled growth of two-dimensional transition metal dichalcogenide (TMD) lateral heterostructures would enable on-demand tuning of electronic and optoelectronic properties in this new class of materials. Prior to this work, compositional modulations in lateral TMD heterostructures have been considered to depend solely on the growth chronology. We show that in-plane diffusion can play a significant role in the chemical vapor deposition of MoS2/WS2 lateral heterostructures leading to a variety of nontrivial structures whose composition does not necessarily follow the growth order. Optical, structural, and compositional studies of TMD crystals captured at different growth temperatures and in different diffusion stages suggest that compositional mixing versus segregation are favored at high and low growth temperatures, respectively. The observed diffusion mechanism will expand the realm of possible lateral heterostructures, particularly ones that cannot be synthesized using traditional methods.
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Affiliation(s)
- Kevin Bogaert
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore , 117546
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Song Liu
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore , 117546
| | - Jordan Chesin
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Denis Titow
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
- Department of Biology and Chemistry, Justus-Liebig-University Giessen , Heinrich-Buff-Ring 17-19, 35392 Giessen, Germany
| | - Silvija Gradečak
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Slaven Garaj
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 6 Science Drive 2, Singapore , 117546
- Department of Physics, National University of Singapore , 2 Science Drive 3, Singapore , 117542
- Department of Biomedical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore , 117575
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