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| 2. |
- Li, Hu, 1986-, et al.
(författare)
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Observation of defect density dependent elastic modulus of graphene
- 2023
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Ingår i: Applied Physics Letters. - 0003-6951 .- 1077-3118. ; 123:5
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Tidskriftsartikel (refereegranskat)abstract
- The recent decade has witnessed a tremendous development of graphene applications in many fields; however, as one of the key considerations, the mechanical properties of graphene still remain largely unexplored. Herein, by employing focused ion beam irradiation, graphene with various defect levels is obtained and further investigated by using Raman spectroscopy and scanning tunneling microscopy. Specially, our atomic force microscopy based nanomechanical property measurement demonstrates a clear defect density dependent behavior in the elastic modulus of graphene on a substrate as the defect density is higher than a threshold value of 1012 cm−2, where a clear decay is observed in the stiffness of graphene. This defect density dependence is mainly attributed to the appearance of amorphous graphene, which is further confirmed with our molecular dynamics calculations. Therefore, our reported result provides an essential guidance to enable the rational design of graphene materials in nanodevices, especially from the perspective of mechanical properties.
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| 3. |
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| 4. |
- Shen, Xiaoling, et al.
(författare)
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Enhancing Photocatalytic Activity of NO Removal through an In Situ Control of Oxygen Vacancies in Growth of TiO2
- 2019
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Ingår i: Advanced Materials Interfaces. - : WILEY. - 2196-7350. ; 6:19
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Tidskriftsartikel (refereegranskat)abstract
- Although defects play an important role in the photocatalytic activity of TiO2, the mechanism of the photocatalytic activity related to different defects remains disputable. Moreover, the reported methods to introduce defects raise the preparation cost. In this work, different types of defects including O-vacancy cluster, surface O-vacancy, and bulk O-vacancy defects are in situ introduced in TiO2 by controlling the crystallization temperature. The medium-degree crystallinity TiO2 sample mainly containing surface O-vacancies exhibits the best NO removal activity. The systematic study of photocatalytic mechanism demonstrates that the surface O-vacancies significantly promote the adsorption of H2O molecules and improve charge transfer to the adsorbed H2O forming center dot OH, thus dramatically enhancing the photocatalytic NO removal activity. On the contrary, bulk O-vacancies neither help the adsorption of H2O molecules, nor improve the charge transfer to H2O.
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| 5. |
- Sun, Jie, et al.
(författare)
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Scanning electron microscopy observation of in-device InAs/AlAs quantum dots by selective etching of capping layers
- 2007
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Ingår i: Modern Physics Letters B. - 0217-9849. ; 21:14, s. 859-866
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembled InAs/AlAs quantum dots embedded in a resonant tunneling diode device structure are grown by molecular beam epitaxy. Through the selective etching in a C6H8O7 center dot H2O-K3C6H5O7 center dot H2O-H2O2 buffer solution, 310 nm GaAs capping layers are removed and the InAs/AlAs quantum dots are observed by field-emission scanning electron microscopy. It is shown that as-fabricated quantum dots have a diameter of several tens of nanometers and a density of 10(10) cm(-2) order. The images taken by this means are comparable or slightly better than those of transmission electron microscopy. The undercut of the InAs/AlAs layer near the edges of mesas is detected and that verifies the reliability of the quantum dot images. The inhomogeneous oxidation of the upper AlAs barrier in H2O2 is also observed. By comparing the morphologies of the mesa edge adjacent regions and the rest areas of the sample, it is concluded that the physicochemical reaction introduced in this letter is diffusion limited.
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| 6. |
- Ye, Xiaoling, et al.
(författare)
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Advances in the Field of Two-Dimensional Crystal-Based Photodetectors
- 2023
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 13:8
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Forskningsöversikt (refereegranskat)abstract
- Two-dimensional (2D) materials have sparked intense interest among the scientific community owing to their extraordinary mechanical, optical, electronic, and thermal properties. In particular, the outstanding electronic and optical properties of 2D materials make them show great application potential in high-performance photodetectors (PDs), which can be applied in many fields such as high-frequency communication, novel biomedical imaging, national security, and so on. Here, the recent research progress of PDs based on 2D materials including graphene, transition metal carbides, transition-metal dichalcogenides, black phosphorus, and hexagonal boron nitride is comprehensively and systematically reviewed. First, the primary detection mechanism of 2D material-based PDs is introduced. Second, the structure and optical properties of 2D materials, as well as their applications in PDs, are heavily discussed. Finally, the opportunities and challenges of 2D material-based PDs are summarized and prospected. This review will provide a reference for the further application of 2D crystal-based PDs.
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| 7. |
- Ye, Xiaoling, et al.
(författare)
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High Performance Self-Powered Photodetectors Based on Graphene Nanoribbons/Al2O3/InGaZnO Heterojunctions
- 2024
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Ingår i: IEEE Photonics Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1943-0655. ; 16:3
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Tidskriftsartikel (refereegranskat)abstract
- Self-powered photodetectors which operate without external power sources hold immense promise in future photodetection systems. To achieve high-performance self-powered optoelectronic devices, efficient electron-hole pair separation is critical to generate high photocurrents. In this work, we successfully synthesized semiconducting graphene nanoribbons (GNRs) with a direct bandgap of 1.80 eV and employed them to construct a high-performance GNR/Al2O3/IGZO heterostructure photodetector. The built-in electric field in the heterojunctions enables this photodetector to exhibit remarkable performance, showing a responsivity of up to 68 mA/W, a detectivity of 8.34 x 1010 Jones, and rapid response times of 21/20 ms at zero bias. Furthermore, the photodetector features a wide spectral detection range of 405 to 1550 nm. These results highlight the promising potential of GNR/IGZO p-n heterojunction-based self-powered photodetectors in optoelectronic applications.
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| 8. |
- Zhao, Mingyue, et al.
(författare)
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Advances in Two-Dimensional Materials for Optoelectronics Applications
- 2022
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Ingår i: Crystals. - : MDPI. - 2073-4352. ; 12:8
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Forskningsöversikt (refereegranskat)abstract
- The past one and a half decades have witnessed the tremendous progress of two-dimensional (2D) crystals, including graphene, transition-metal dichalcogenides, black phosphorus, MXenes, hexagonal boron nitride, etc., in a variety of fields. The key to their success is their unique structural, electrical, mechanical and optical properties. Herein, this paper gives a comprehensive summary on the recent advances in 2D materials for optoelectronic approaches with the emphasis on the morphology and structure, optical properties, synthesis methods, as well as detailed optoelectronic applications. Additionally, the challenges and perspectives in the current development of 2D materials are also summarized and indicated. Therefore, this review can provide a reference for further explorations and innovations of 2D material-based optoelectronics devices.
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