Nanocristais coloidais de semicondutores II-VI e IV-VI

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

This thesis studies colloidal nanocrystals of II-VI and IV-VI in the quantum confinement regime (quantum dots). This work with colloidal systems is the first in our group. The interest on these systems comes from the fact that it could explain the splitting of the fundamental state, due to the presence of stress-strain on the quantum dots interface with the glass matrix. The synthesis of these nanocrystals utilizes recent methods to produce nearly monodisperse CdSe nanocrystals with radius of about 1,7 nm and a dispersion of 3,8%. The dependence of size when water is added to the system can be observed, whose tendency is to increase. We have presented a discussion about the reaction kinetics with emphasis on the broadening and narrowing of the size distribution, depending on the size of the critical radius. Besides the colloidal synthesis, the experimental techniques adopted in this work where: transmission electron microscopy and optical absorption. For the optical absorption, we used the theory, already studied by our group, now applied to a wurtzite material. A program was elaborated to determine the energy levels for tabulated parameters. The results of this model were used in our interpretation of the experimental results

ASSUNTO(S)

coloides analise espectral teoria de faixa de energia de solidos quimica - sintese semicondutores microscopio eletronico - transmissão

ACESSO AO ARTIGO

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