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Gao X, Pang G, Ni Z, Chen R. Surface-Related Exciton and Lasing in CdS Nanostructures. NANOSCALE RESEARCH LETTERS 2019; 14:216. [PMID: 31240461 PMCID: PMC6592998 DOI: 10.1186/s11671-019-3036-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 05/30/2019] [Indexed: 06/09/2023]
Abstract
In this report, comparative investigation of photoluminescence (PL) characteristics of CdS nanobelts (NBs) and nanowires (NWs) is presented. At low temperatures, emissions originate from radiative recombination of free exciton A, neutral donor bound exciton, neutral acceptor bound exciton and surface related exciton (SX) are observed and analyzed through power-dependent and temperature-dependent PL measurements. We found that SX emission takes a predominant role in emissions of CdS nanobelts and nanowires. There is a direct correlation between SX emission intensity and surface-to-volume ratio, which is the SX emission intensity is proportional to the superficial area of the nanostructures. At the same time, we found that the exciton-phonon interaction in the CdS NWs sample is weaker than that of CdS NBs sample. Furthermore, lasing action has been observed in CdS NBs sample at room temperature with lasing threshold of 608.13 mW/cm2. However, there is no lasing emission in CdS NWs sample. This phenomenon can be explained by the side effects (such as thermal effects) from surface deep level transitions caused the lower damage threshold in CdS NWs. Based on the observations and deductions presented here, SX emission significantly impact on the performance of nanostructures for lasing and light-emitting applications.
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Affiliation(s)
- Xian Gao
- Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055 People’s Republic of China
- School of Physics, Southeast University, Nanjing, 211189 People’s Republic of China
| | - Guotao Pang
- Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055 People’s Republic of China
| | - Zhenhua Ni
- School of Physics, Southeast University, Nanjing, 211189 People’s Republic of China
| | - Rui Chen
- Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055 People’s Republic of China
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Tang Z, Xu T, Li S, Shi Z, Li X. Room-temperature excitonic emission with a phonon replica from graphene nanosheets deposited on Ni-nanocrystallites/Si-nanoporous pillar array. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172238. [PMID: 30224993 PMCID: PMC6124105 DOI: 10.1098/rsos.172238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
Graphene nanosheets (GNSs) were grown on a Si nanoporous pillar array (Si-NPA) via chemical vapour deposition, using a thin layer of pre-deposited Ni nanocrystallites as catalyst. GNSs were determined to be of high quality and good dispersivity, with a typical diameter size of 15 × 8 nm. Light absorption measurements showed that GNSs had an absorption band edge at 3.3 eV. They also showed sharp and regular excitonic emitting peaks in the ultraviolet and visible region (2.06-3.6 eV). Moreover, phonon replicas with long-term stability appeared with the excitonic peaks at room temperature. Temperature-dependent photoluminescence from the GNSs revealed that the excitonic emission derived from free and bound excitonic recombination. A physical model based on band energy theory was constructed to analyse the carrier transport of GNSs. The Ni nanocrystallites on Si-NPA, which acted as a metal-enhanced fluorescence substrate, were supposed to accelerate the excitonic recombination of GNSs and enhanced the measured emission intensity. Results of this study would be valuable in determining the luminescence mechanism of GNSs and could be applied in real-world optoelectronic devices.
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Affiliation(s)
- Zhaojun Tang
- Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450001, People's Republic of China
- Electrical Engineering Department, Zhengzhou Business Technician Institute, Zhengzhou 450100, People's Republic of China
| | - Tingting Xu
- Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450001, People's Republic of China
| | - Sen Li
- Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450001, People's Republic of China
| | - Zhifeng Shi
- Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450001, People's Republic of China
| | - Xinjian Li
- Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450001, People's Republic of China
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Sarau G, Heilmann M, Bashouti M, Latzel M, Tessarek C, Christiansen S. Efficient Nitrogen Doping of Single-Layer Graphene Accompanied by Negligible Defect Generation for Integration into Hybrid Semiconductor Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2017; 9:10003-10011. [PMID: 28244739 DOI: 10.1021/acsami.7b00067] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
While doping enables application-specific tailoring of graphene properties, it can also produce high defect densities that degrade the beneficial features. In this work, we report efficient nitrogen doping of ∼11 atom % without virtually inducing new structural defects in the initial, large-area, low defect, and transferred single-layer graphene. To shed light on this remarkable high-doping-low-disorder relationship, a unique experimental strategy consisting of analyzing the changes in doping, strain, and defect density after each important step during the doping procedure was employed. Complementary micro-Raman mapping, X-ray photoelectron spectroscopy, and optical microscopy revealed that effective cleaning of the graphene surface assists efficient nitrogen incorporation accompanied by mild compressive strain resulting in negligible defect formation in the doped graphene lattice. These original results are achieved by separating the growth of graphene from its doping. Moreover, the high doping level occurred simultaneously with the epitaxial growth of n-GaN micro- and nanorods on top of graphene, leading to the flow of higher currents through the graphene/n-GaN rod interface. Our approach can be extended toward integrating graphene into other technologically relevant hybrid semiconductor heterostructures and obtaining an ohmic contact at their interfaces by adjusting the doping level in graphene.
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Affiliation(s)
- George Sarau
- Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany
- Max Planck Institute for the Science of Light , Staudtstrasse 2, 91058 Erlangen, Germany
| | - Martin Heilmann
- Max Planck Institute for the Science of Light , Staudtstrasse 2, 91058 Erlangen, Germany
| | - Muhammad Bashouti
- Max Planck Institute for the Science of Light , Staudtstrasse 2, 91058 Erlangen, Germany
- Jacob Blaustein Institutes for Desert Research, Sede Boqer Campus, Ben-Gurion University of the Negev , 8499000 Sede Boqer, Israel
| | - Michael Latzel
- Max Planck Institute for the Science of Light , Staudtstrasse 2, 91058 Erlangen, Germany
- Institute of Optics, Information and Photonics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Staudtstrasse 7/B2, 91058 Erlangen, Germany
| | - Christian Tessarek
- Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany
- Max Planck Institute for the Science of Light , Staudtstrasse 2, 91058 Erlangen, Germany
| | - Silke Christiansen
- Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany
- Max Planck Institute for the Science of Light , Staudtstrasse 2, 91058 Erlangen, Germany
- Physics Department, Freie Universität Berlin , Arnimallee 14, 14195 Berlin, Germany
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Gao X, Wei Z, Zhao F, Yang Y, Chen R, Fang X, Tang J, Fang D, Wang D, Li R, Ge X, Ma X, Wang X. Investigation of Localized States in GaAsSb Epilayers Grown by Molecular Beam Epitaxy. Sci Rep 2016; 6:29112. [PMID: 27381641 PMCID: PMC4933967 DOI: 10.1038/srep29112] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/15/2016] [Indexed: 01/29/2023] Open
Abstract
We report the carrier dynamics in GaAsSb ternary alloy grown by molecular beam epitaxy through comprehensive spectroscopic characterization over a wide temperature range. A detailed analysis of the experimental data reveals a complex carrier relaxation process involving both localized and delocalized states. At low temperature, the localized degree shows linear relationship with the increase of Sb component. The existence of localized states is also confirmed by the temperature dependence of peak position and band width of the emission. At temperature higher than 60 K, emissions related to localized states are quenched while the band to band transition dominates the whole spectrum. This study indicates that the localized states are related to the Sb component in the GaAsSb alloy, while it leads to the poor crystal quality of the material, and the application of GaAsSb alloy would be limited by this deterioration.
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Affiliation(s)
- Xian Gao
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Zhipeng Wei
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Fenghuan Zhao
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology of China, Shenzhen, Guangdong 518055, China
| | - Yahui Yang
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology of China, Shenzhen, Guangdong 518055, China
| | - Rui Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology of China, Shenzhen, Guangdong 518055, China
| | - Xuan Fang
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Jilong Tang
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Dan Fang
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Dengkui Wang
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Ruixue Li
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Xiaotian Ge
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Xiaohui Ma
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
| | - Xiaohua Wang
- State Key Laboratory of High Power Semiconductor Laser, School of Science, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022, China
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Three-dimensional Aerographite-GaN hybrid networks: single step fabrication of porous and mechanically flexible materials for multifunctional applications. Sci Rep 2015; 5:8839. [PMID: 25744694 PMCID: PMC4351516 DOI: 10.1038/srep08839] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/06/2015] [Indexed: 02/01/2023] Open
Abstract
Three dimensional (3D) elastic hybrid networks built from interconnected nano- and microstructure building units, in the form of semiconducting-carbonaceous materials, are potential candidates for advanced technological applications. However, fabrication of these 3D hybrid networks by simple and versatile methods is a challenging task due to the involvement of complex and multiple synthesis processes. In this paper, we demonstrate the growth of Aerographite-GaN 3D hybrid networks using ultralight and extremely porous carbon based Aerographite material as templates by a single step hydride vapor phase epitaxy process. The GaN nano- and microstructures grow on the surface of Aerographite tubes and follow the network architecture of the Aerographite template without agglomeration. The synthesized 3D networks are integrated with the properties from both, i.e., nanoscale GaN structures and Aerographite in the form of flexible and semiconducting composites which could be exploited as next generation materials for electronic, photonic, and sensors applications.
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