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Carlos L. Trallero Giner | Faculty of Physics/University of Havana - Cuba

Processo: 05/04776-7
Linha de fomento:Auxílio à Pesquisa - Pesquisador Visitante - Internacional
Vigência: 05 de abril de 2006 - 10 de setembro de 2006
Área do conhecimento:Ciências Exatas e da Terra - Física - Física da Matéria Condensada
Pesquisador responsável:Gilmar Eugenio Marques
Beneficiário:Gilmar Eugenio Marques
Pesquisador visitante: Carlos L. Trallero Giner
Inst. do pesquisador visitante: Universidad de La Habana (UH), Cuba
Instituição-sede: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brasil
Assunto(s):Fônons  Éxciton  Heteroestruturas  Intercâmbio de pesquisadores 

Resumo

Part I: - Multi-phonon resonant Raman scattering in quantum wells. The emission spectra contain a set of emission lines with resonant frequencies (wL - wLO), where wL is the incident radiation frequency, wLO is the emitted LO-phonon frequency, and N represents the number of phonons involved in the emission. These LO-phonon lines are considered as multi-phonon resonant Raman scattering (MPRS) processes. The relative intensities of these MPR scattering processes are very sensitive to the quantum well width. Project: - Investigate the Raman selection rules of MPRS in III-V and II-VI quantum wells. - Evaluate the Raman MPRS intensities and excitation-energy, indirect exciton creation probability by the light, exciton cascade scattering probability, and the indirect annihilation probability assisted by LO-phonons as a function of the QW width, exciton kinetic energy and phonon modes. Part II. Phonons in Zinc Oxide nanostructures.Several ZnO nanostructures with different geometry are been synthesized: Nanorings, nanobelts, nonowires of ZnO can be obtained under specific grown conditions. The Raman resonant line-shapes, due to first and higher order phonon processes, should show structures involving the combination of confined and interfacial optical modes. Project: - Calculate the frequency dependence of confined and interface optical modes for the geometries, material parameters, as well as the electron–phonon interaction Hamiltonian using electrical and mechanical coupling model. Evaluate the electron-optical phonon deformation potential Hamiltonian for the case of ZnO nanowires. - Evaluate the electron-optical phonon deformation potential Hamiltonian for the case of ZnO nanorods, and determine the optical Raman selection rules for ZnO nanowires and nanoroads. Part III : - Non-linear optical responses in quantum dots-The project is intended to develop a theoretical study of two-photon absorption processes and nonlinear optical responses in semiconductor Quantum Dots. Other important applications of non-linear optical responses are: optoelectronic, sensors, piezoelectric transducer, UV detectors, biomedical science, among others. The small volume of quantum dots allows also the study of a series of new observed intrinsic non-linear characteristics such as dark linear optical transitions. Parte IV: Espalhamento Inelástico da Luz em Sistemas Semicondutores Quase-Zero-Dimensionais: Efeitos da Interação Spin-órbita. Os modelos teóricos são muito valiosos na interpretação dos bastante complexos espectros Raman em Nanoestruturas. O espalhamento micro-Raman nestes sistemas é promissor e versátil no diagnóstico de estados ligados de spin. Projeto: Fazer simulação teórica da resposta inelástica para obtenção de informações complementares dentro do efeito Raman ressonante e do não-ressonante. Estudar possíveis efeitos anômalos associados ao spin eletrônico e espalhamento Raman do tipo spin-flip que permitiria o estudo dos estados desdobrados Zeeman. (AU)