RESUMO
A theoretical and experimental study of isolated nanoparticles of II-VI semiconductor materials has been done. Using the framework of the effective mass model, the optical absorption spectrum of distributions of spherical quantum dots, freestanding, and under compressive or tensile stress, has been examined theoretically. The theoretical results allow one to foresee the absorption spectra of quantum dots made of a series of materials and having any size. The syntheses of colloidal quantum dots of CdS and CdSe has also been performed through wet chemical routes and characterized by means of optical techniques. The values of the strains in the synthesized quantum dots were inferred from a correlation established between the theoretical and the experimental results.
Assuntos
Simulação por Computador , Modelos Químicos , Nanopartículas/química , Teoria Quântica , Semicondutores , Compostos de Cádmio/síntese química , Compostos de Cádmio/química , Teste de Materiais , Tamanho da Partícula , Pontos Quânticos , Compostos de Selênio/síntese química , Compostos de Selênio/química , Sulfetos/síntese química , Sulfetos/químicaRESUMO
The growth kinetics of CdTe colloidal nanocrystals has been analyzed quantitatively by means of dynamic light scattering and photoluminescence measurements. The growth rates, size distributions, critical radii, and diffusion constants have been calculated in the framework of the Sugimoto theoretical model. A two-step diffusion-controlled growth regime has been proposed for the reported synthesis and a set of relations for the time evolution of the size distribution has been derived and discussed in the sense of the size distribution focusing concept.