P. M. Coelho, et al., “Near-edge X-ray absorption spectroscopy signature of image potential states in multilayer epitaxial graphene,” Surface Science, vol. 644, pp. 135-140, 2016. Publisher's VersionAbstract
Single layer behavior in multilayer epitaxial graphene has been a matter of intense investigation. This is due to the layer decoupling that occurs during growth of graphene on some types of substrates, such as carbon-terminated silicon carbide. We show here that near-edge X-ray absorption spectroscopy can be used to observe the signature of this decoupling. To this end, samples of multilayer graphene from silicon carbide sublimation were grown with different degrees of decoupling. Raman spectroscopy was used to infer the degree of structural decoupling. X-ray grazing-incidence diffraction and scanning tunneling microscopy showed that growth initiates with the presence of bilayer graphene commensurate structures, while layer decoupling is associated to the formation of incommensurate structures observed for longer sublimation time. Near-edge X-ray absorption spectroscopy was used to probe the electronic states above the Fermi energy. Besides the σ* and π* empty states, image potential states are observed and show a clear change of intensity as a function of incident angle. These image potential states evolve from a graphite- to graphene-like behavior as a function of growth time and can be used to infer the degree of structural coupling among layers.
R. Sathyavathi, et al., “Raman spectroscopic sensing of carbonate intercalation in breast microcalcifications at stereotactic biopsy,” Scientific Reports, vol. 5, pp. 9907 EP -, 2015. Publisher's Version
A. B. Alencar, A. P. M. Barboza, B. S. Archanjo, H. Chacham, and B. R. A. Neves, “Experimental and theoretical investigations of monolayer and few-layer talc,” 2d Materials, vol. 2, no. 1, 2015. Publisher's Version
C. K. Oliveira, et al., “Crystal-oriented wrinkles with origami-type junctions in few-layer hexagonal boron nitride,” Nano Research, vol. 8, no. 5, pp. 1680-1688, 2015. Publisher's Version
R. Nascimento, J. R. da Martins, R. J. C. Batista, and H. Chacham, “Band Gaps of BN-Doped Graphene: Fluctuations, Trends, and Bounds,” Journal of Physical Chemistry C, vol. 119, no. 9, pp. 5055-5061, 2015. Publisher's Version
S. M. Manhabosco, R. J. C. Batista, S. Neves da Silva, and L. F. P. Dick, “DETERMINATION OF CURRENT MAPS BY SVET OF HOT-DIP GALVANIZED STEEL UNDER SIMULTANEOUS STRAINING,” Electrochimica Acta, vol. 168, pp. 89-96, 2015. Publisher's Version
K. A. S. Araujo, et al., “Charge transfer between carbon nanotubes on surfaces,” Nanoscale, vol. 7, no. 39, pp. 16175-16181, 2015. Publisher's Version
A. L. de Lima, L. A. M. Muessnich, T. M. Manhabosco, H. Chacham, R. J. C. Batista, and A. B. Oliveira, “Soliton instability and fold formation in laterally compressed graphene,” Nanotechnology, vol. 26, no. 4, 2015. Publisher's Version
M. C. Prado, R. Nascimento, B. E. N. Faria, M. J. S. Matos, H. Chacham, and B. R. A. Neves, “Nanometre-scale identification of grain boundaries in MoS 2 through molecular decoration,” Nanotechnology, vol. 26, no. 47, pp. 475702, 2015. Publisher's VersionAbstract
In this paper, we address the challenge of identifying grain boundaries on the molybdenum disulphide (MoS 2 ) surface at the nanometre scale using a simple self-assembled monolayer (SAM) decoration method. Combined with atomic force microscopy, octadecylphosphonic acid monolayers readily reveal grain boundaries in MoS 2 at ambient conditions, without the need of atomic resolution measurements under vacuum. Additional ab initio calculations allow us to obtain the preferred orientation of the SAM structure relative to the MoS 2 beneath, and therefore, together with the experiments, the MoS 2 crystalline orientations at the grain boundaries. The proposed method enables the visualization of grain boundaries with sub-micrometer resolution for nanodevice investigation and failure analysis.
A. M. Marques dos Santos, et al., “Corrosion and cell viability studies of graphite-like hydrogenated amorphous carbon films deposited on bare and nitrided titanium alloy,” Corrosion Science, vol. 82, pp. 297-303, 2014. Publisher's Version
R. J. C. Batista, S. S. Carara, T. M. Manhabosco, and H. Chacham, “A Ferromagnetic Pure Carbon Structure Composed of Graphene and Nanotubes: First-Principles Calculations,” Journal of Physical Chemistry C, vol. 118, no. 15, pp. 8143-8147, 2014. Publisher's Version
N. A. Yoshioka, H. L. Ramos Rocha, T. Cazati, T. M. Manhabosco, and I. L. Mueller, “Pulsed Electrodeposition of Polyaniline Films Used as Photogenerated Charge Transporting Layers in Organic Photovoltaic Devices,” Polimeros-Ciencia E Tecnologia, vol. 24, no. 1, pp. 88-93, 2014. Publisher's Version
R. J. C. Batista, A. B. Oliveira, S. S. Carara, and H. Chacham, “Controlling the Electrical Response of Carbon Nanotubes Deposited on Diamond through the Application of Electric Fields,” Journal of Physical Chemistry C, vol. 118, no. 37, pp. 21599-21603, 2014. Publisher's Version
M. de Pauli, et al., “Chemical Stabilization and Improved Thermal Resilience of Molecular Arrangements: Possible Formation of a Surface Network of Bonds by Multiple Pulse Atomic Layer Deposition,” Journal of Physical Chemistry B, vol. 118, no. 32, pp. 9792-9799, 2014.
M. J. S. Matos, M. S. C. Mazzoni, and H. Chacham, “Graphene-boron nitride superlattices: the role of point defects at the BN layer,” Nanotechnology, vol. 25, no. 16, 2014.
L. M. Malard, T. V. Alencar, A. P. M. Barboza, K. F. Mak, A. M. de Paula, and Ieee, “Imaging the crystal structure of few-layer two-dimensional crystals by optical nonlinearity,” in 2013 Conference on Lasers and Electro-Optics, 2013. Publisher's Version
L. M. Malard, T. V. Alencar, A. P. M. Barboza, K. F. Mak, and A. M. de Paula, “Observation of intense second harmonic generation from MoS2 atomic crystals,” Physical Review B, vol. 87, no. 20, 2013. Publisher's Version
T. M. Manhabosco, et al., “Cell response and corrosion behavior of electrodeposited diamond-like carbon films on nanostructured titanium,” Corrosion Science, vol. 66, pp. 169-176, 2013. Publisher's Version
T. M. Manhabosco, A. P. M. Barboza, R. J. C. Batista, B. R. A. Neves, and I. L. Mueller, “Corrosion, wear and wear-corrosion behavior of graphite-like a-C:H films deposited on bare and nitrided titanium alloy,” Diamond and Related Materials, vol. 31, pp. 58-64, 2013. Publisher's Version
V. Carozo, et al., “Resonance effects on the Raman spectra of graphene superlattices,” Physical Review B, vol. 88, no. 8, 2013.