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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Caracterização estrutural de pontos quânticos e filmes ultrafinos de CdTe/Si(111) / Structural characterization of CdTe/Si(111) quantum dots and ultra-thin films

Suela, Jefferson 09 March 2007 (has links)
Made available in DSpace on 2015-03-26T13:35:24Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2255864 bytes, checksum: 3379a54f5490338aa78351418a7c806a (MD5) Previous issue date: 2007-03-09 / This work aims the morphological and structural characterization of CdTe quantum dots and ultra-thin films grown on Si(111) substrates with hydrogen-terminated surface. The samples were grown by hot wall epitaxy and investigated by atomic force microscopic and specular and grazing incidence X-ray diffraction. Analysis of the atomic force microscopy images shows the presence of isolated pyramidal CdTe islands indicating that the quantum dots follow the Volmer-Weber growth mode. The X-ray diffraction results show that despite a large mismatch (19%) the islands grow epitaxially, following the [111] substrate orientation. The X-ray measurements make also possible the determination of the vertical and lateral dimensions of the islands and the observation that some islands are rotated by 30o degrees in the growth plane. / Neste trabalho, foi feita a caracterização estrutural e morfológica de pontos quânticos e filmes ultrafinos de CdTe crescidos sobre substrato de Si(111) passivado com hidrogênio. As amostras foram crescidas por epitaxia de paredes quentes e caracterizadas por microscopia de força atômica e difração de raios- especular e incidência rasante.As analises das imagens de microscopia de força atômica mostram a existência de ilhas isoladas de formato piramidal, mostrando que o crescimento segue o modo Volmer-Weber. As medidas de difração de raios-X, mostram que apesar do considerável descasamento do parâmetro de rede (19%) as ilhas crescem epitaxialmente, seguindo a direção cristalográfica [111] do substrato de silício. A analise cuidadosa das medidas de difração com incidência rasante permite determinar as dimensões lateral e vertical dos pontos quânticos e a observar existência de uma pequena quantidade de pontos quânticos girados de 30º no plano de crescimento.

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