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Nanoparticles and graphene-like materials

Scientific highlights

Electronic structure and optical properties of semiconductor nanowires polytypes

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Advances in the fabrication and characterization of nanowires polytypes have made crystal phase engineering a well-established tool to tailor material properties. In this review, recent progresses in the field are described, with special focus on the central role that crystal phase has in modulating the electronic and optical properties of nanowires. We start with an overview on III-V nanowires, which have been developed first and for which more experimental results already exist. Then, particular attention will be devoted to group IV polytypes which represent one of the most exciting and novel topic in the field. A survey of both theoretical and experimental efforts will be provided with the final aim of highlighting the importance of crystal phase control in materials design.
Full text at: DOI https://doi-org.proxy.scd.u-psud.fr/10.1140/epjb/e2019-100375-7

Interplay Between Cr Dopants and Vacancy Clustering in the Structural and Optical Properties of WSe2

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Here, we analyze the effect of Cr doping on WSe2 crystals. The topology and the chemistry of the doped samples have been investigated by atom-resolved STEM microscopy combined with EEL spectroscopy. Cr (measured to have formal valence 3+) occupies W sites (formal valence 4+), indicating a possible hole doping. However, single or double Se-vacancies cluster near Cr atoms, leading to an effective electron doping. These defects organization can be explained by the strong binding energy of the CrW—Vse complex obtained by in DFT calculations. In highly Cr-doped samples, a local phase transition from the 2H to the to 1T phase is observed, which has been previously reported for other electron-doped transition metal dichalcogenides. Cr-doped crystals suffers a compressive strain, resulting in an isotropic lattice contraction and in an anisotropic optical bandgap energy shift (25 meV in-plane and 80 meV out-of-plane).


C-H. Ho, W-H. Chen, K.K. Tiong, K-Y. Lee, A. Gloter, A. Zobelli, O. Stephan, and L. H. G. Tizei, ACS nano (2017)

Publications

Tizei, L.H.G., et al. Tailored nanoscale plasmon-enhanced vibrational electron spectroscopy. Nano Letters (2020).doi:10.1021/acs.nanolett.9b04659
Karapinar, D., et al. Carbon-Nanotube-Supported Copper Polyphthalocyanine for Efficient and Selective Electrocatalytic CO 2 Reduction to CO. ChemSusChem 110627133819613867946813834931339326416013813910712224519085252, (2019).
Amato, M., Kaewmaraya, T., Zobelli, A., Palummo, M. & Rurali, R. Crystal Phase Effects in Si Nanowire Polytypes and Their Homojunctions. Nano Letters 16, 5694–5700 (2016).
Bourrellier, R., et al. Bright UV Single Photon Emission at Point Defects in h -BN. Nano Letters 16, 4317 (2016).
Tararan, A., Zobelli, A., Benito, A.M., Maser, W.K. & Stéphan, O. Revisiting Graphene Oxide Chemistry via Spatially-Resolved Electron Energy Loss Spectroscopy. Chemistry of Materials 28, 3741 (2016).
Arenal, R., et al. Atomic Configuration of Nitrogen-Doped Single-Walled Carbon Nanotubes. Nano Letters 14, 5509 - 5516 (2014).
Bourrellier, R., et al. Nanometric Resolved Luminescence in h-BN Flakes: Excitons and Stacking Order. ACS Photonics 1, (2014). Download: bourrellier-acs-photonics.pdf (7.37 MB)
Walls, M., et al. Identification of Ferrous-Ferric Fe3O4 Nanoparticles in Recombinant Human Ferritin Cages. Microscopy and Microanalysis 19, 835 - 841 (2013).
Yang, Z., Walls, M., Lisiecki, I. & Pileni, M.-P. Unusual Effect of an Electron Beam on the Formation of Core/Shell (Co/CoO) Nanoparticles Differing by Their Crystalline Structures. Chemistry of Materials 25, 2372 - 2377 (2013).
Mignot, A., et al. A Top-Down Synthesis Route to Ultrasmall Multifunctional Gd-Based Silica Nanoparticles for Theranostic Applications. Chemistry - A European Journal n/a - n/a (2013).doi:10.1002/chem.201203003 Download: Mignot_Chemistry13_NPs-SiGd.pdf (2.51 MB)
Santana, A., Zobelli, A., Kotakoski, J., Chuvilin, A. & Bichoutskaia, E. Inclusion of radiation damage dynamics in high-resolution transmission electron microscopy image simulations: The example of graphene. Physical Review B 87, (2013).
Eswara Moorthy, S.K., Rousseau, O., Viret, M. & Kociak, M. Nanoscale Chemical and Structural Characterization of Transient Metallic Nanowires using Aberration-Corrected STEM-EELS. Nano Letters 12, 2732 - 2739 (2012). Download: nl204374v.pdf (1.74 MB)
Zobelli, A., et al. A comparative study of density functional and density functional tight binding calculations of defects in graphene. physica status solidi (b) 249, 276 - 282 (2012). Download: zobelli_pssb_2012.pdf (2.01 MB)
Cavalier, M., Walls, M., Lisiecki, I. & Pileni, M.P. How Can the Nanocrystallinity of 7 nm Spherical Co Nanoparticles Dispersed in Solution Be Improved?. Langmuir 27, 5014–5020 (2011).
Susi, T., et al. Nitrogen-Doped Single-Walled Carbon Nanotube Thin Films Exhibiting Anomalous Sheet Resistances. Chemistry Of Materials 23, 2201–2208 (2011).
Trasobares, S., et al. Chemical Imaging at Atomic Resolution as a Technique To Refine the Local Structure of Nanocrystals. Angewandte Chemie-International Edition 50, 868–872 (2011). Download: Angew. Chem. Int. Ed. 2011 Trasobares.pdf (649.98 KB)
Ivanovskaya, V.V., et al. Low-Energy Termination of Graphene Edges via the Formation of Narrow Nanotubes. Physical Review Letters 107, 065502 (2011). Download: PhysRevLett.107.065502.pdf (506.32 KB)
Ivanovskaya, V.V., et al. Hydrogen adsorption on graphene: a first principles study. The European Physical Journal B 76, 481 - 486 (2010). Download: H-at-Graphene.pdf (254.61 KB)
Rodriguez-Lorenzo, L., et al. Zeptomol Detection Through Controlled Ultrasensitive Surface-Enhanced Raman Scattering. Journal Of The American Chemical Society 131, 4616–+ (2009). Download: J. Am. Chem. Soc. 2009 Rodríguez-Lorenzo.pdf (927.32 KB)
Arenal, R., et al. Optical gap measurements on individual boron nitride nanotubes by electron energy loss spectroscopy. Microscopy And Microanalysis 14, 274–282 (2008).
Zobelli, A., Gloter, A., Ewels, C.P. & Colliex, C. Shaping single walled nanotubes with an electron beam. Physical Review B 77, 045410 (2008). Download: PhysRevB.77.045410.pdf (1.13 MB)
Nelayah, J., et al. Mapping surface plasmons on a single metallic nanoparticle. Nature Physics 3, 348–353 (2007). Download: Nat Phys 2007 Nelayah.pdf (676.34 KB)
Zobelli, A., Gloter, A., Ewels, C.P., Seifert, G. & Colliex, C. Electron knock-on cross section of carbon and boron nitride nanotubes. Physical Review B 75, (2007). Download: crosssec.pdf (399.11 KB)
Zobelli, A., et al. Defective Structure of BN Nanotubes:  From Single Vacancies to Dislocation Lines. Nano Letters 6, 1955 - 1960 (2006).
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