Encontrados 40 documentos, a visualizar página 1 de 4
Exciton migration in self-assembled dendrite-type fractal superstructures of mo...
Bernardo, César; Belsley, M.; Coutinho, Paulo J. G.; Schellenberg, Peter; Moura, Isabel; Núñez Fernández, Yuriel; Stauber, Tobias; Vasilevskiy, MikhailWe investigated dendrite shaped superstructures made of two different QDs, namely CdSe/ZnS and CdTe. Due to the dense packing of QDs, Förster resonance energy transfer (FRET) may compete with deexcitation, and the specific dendrite shaped structure suggests the possibility of funneling of excitation from the edges of the structure to the center.
Surface plasmon resonance of sparsely dispersed au nanoparticles in TiO2 photoa...
Samantilleke, A. P.; Vasilevskiy, Mikhail; Rodrigues, N. F. G.; Cerqueira, Fátima; Mari, BernabePlasmonics is an emerging field that makes use of the nanoscale properties of metals, and its application in solar cells has seen a recent surge of interest [1]. Dye-sensitized solar cells (DSSC) were fabricated by incorporating Au NPs into the TiO2 photoanode. The dye absorption is enhanced by the strong localized electric field from localized surface plasmon and the recombination and back reaction of electron...
A primer on surface plasmon-polaritons in graphene
Bludov, Yuliy V.; Ferreira, Aires; Peres, N. M. R.; Vasilevskiy, MikhailWe discuss the properties of surface plasmons-polaritons in graphene and describe four possible ways of coupling electromagnetic radiation in the terahertz (THz) spectral range to this type of surface waves: (i) the attenuated total reflection (ATR) method us- ing a prism in the Otto configuration, (ii) graphene micro-ribbon arrays or monolayers with modulated conductivity, (iii) a metal stripe on top of the gr...
Unusual reflection of electromagnetic radiation from a stack of graphene layers...
Bludov, Yuliy V.; Peres, N. M. R.; Vasilevskiy, MikhailWe study the interaction of electromagnetic (EM) radiation with single-layer graphene and a stack of parallel graphene sheets at arbitrary angles of incidence. It is found that the behavior is qualitatively different for transverse magnetic (or p-polarized) and transverse electric (or s-polarized) waves. In particular, the absorbance of single-layer graphene attains a minimum (maximum) for the p (s)-polarizatio...
Exact solution for square-wave grating covered with graphene : surface plasmons...
Peres, N. M. R.; Bludov, Yuliy V.; Ferreira, Aires; Vasilevskiy, MikhailWe provide an analytical solution to the problem of scattering of electromagnetic radiation by a square-wave grating with a flat graphene sheet on top.We show that for deep groves there is a strong plasmonic response, with light absorption in the graphene sheet reaching more than 45% due to the excitation of surface plasmon-polaritons. The case of a grating with a graphene sheet presenting an induced periodic m...
Nano-ilmenite FeTiO3 : synthesis and characterization
Raghavender, A. T.; Hoa Hong, Nguyen; Lee, Kyu Joon; Jung, Myung-Hwa; Skoko, Z.; Vasilevskiy, Mikhail; Cerqueira, M. F.; Samantilleke, A. P.In general, ilmenite FeTiO3 is synthesized by solid-state reaction at very high pressure and high temperature. Synthesis of FeTiO3 is not an easy task as the Fe2+ ions are not stable. Therefore, it is really challenging to prepare this material. In this work nano-ilmenite FeTiO3 was synthesized by the sol-gel method. Structural, optical and magnetic characterizations were performed. The bandgap of FeTiO3 was de...
Condensed exciton polaritons in a two-dimensional trap : elementary excitations...
Núñez Fernández, Yuriel; Vasilevskiy, Mikhail; Trallero-Giner, Carlos; Kavokin, AlexeyAn exciton-polariton condensate (EPC) confined in a parabolic two-dimensional trap is considered theoretically. In the realistic limit of weakly interacting polaritons, the nonlinear term in the Gross-Pitaevskii equation describing the properties of the condensate can be considered as a perturbationwith respect to the trapping potential, which allows for a convenient analytical description of the EPC ground sta...
Resonance energy transfer in self-organized organic/inorganic dendrite structures
Melnikau, D.; Savateeva, D.; Lesnyak, V.; Gaponik, Nikolai; Núnez Fernández, Yuriel; Vasilevskiy, Mikhail; Costa, M. F.; Mochalov, K. E.; Oleinikov, V.Hybrid materials formed by semiconductor quantum dots and J-aggregates of cyanine dyes provide a unique combination of enhanced absorption in inorganic constituents with large oscillator strength and extremely narrow exciton bands of the organic component. The optical properties of dendrite structures with fractal dimension 1.7–1.8, formed from J-aggregates integrated with CdTe quantum dots (QDs), have been inv...
Phonon modes and raman scattering in SixGe1-x nanocrystals : microscopic modelling
Vasin, Alexander; Vikhrova, Olga; Vasilevskiy, MikhailSi1-xGex nanocrystals (NCs) of different composition and size were generated using the Molecular Dynamics (MD) method by minimizing NC’s total energy calculated using Tersoff’s empirical potential and applying rigid boundary conditions. The dynamical matrix of the relaxed NC was constructed and the NC phonon modes were calculated. The localisation of the principal (Si-Si, Si-Ge and Ge-Ge) modes is investigated ...
Light emission and spin-polarised hole injection in InAs/GaAs quantum dot heter...
Baidus, N. V.; Vasilevskiy, Mikhail; Khazanova, S. V.; Zvonkov, B. N.; Meulen, H. P. van der; Calleja, J. M.; Vinã, L.EPL draft ; We demonstrate the feasibility to obtain electroluminescence (EL), up to room temperature, from InGaAs self-assembled quantum dots (QDs) included in a forward-biased Schottky diode. Moreover, using a ferromagnet (FM) as the contact layer, sizable circular polarization of the EL emission in the presence of an external magnetic eld is obtained. A resonant behav- ior of the degree of circular polariz...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||