NANOESTRUTURAS DE ZNO ALTAMENTE LUMINESCENTE: SYNTESIS Y CARACTERIZACIÓN / NANOESTRUTURAS DE ZNO ALTAMENTE LUMINESCENTE: SÍNTESE E CARACTERIZAÇÃO / HIGHLY LUMINESCENT ZNO NANOESTRUCTURES: SYNTHESIS AND CHARACTERIZATION

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Zinc Oxide hás been synthesized by evaporation, condensation, and oxidation of methallic zinc under atmospheric pressure. Two methods of synthesis, denominated stationary and dynamic, were developed in this study. In the stationary system has the local control of temperature and a alumina tube-furnace reactor has been used. Zn was evaporated at 900-1000 C in an alumina tube under controlled pressure and heating profile. Pieces of Zn were introduced into the alumina tube. During heating, the ambient oxygen reacted with the Zn surfcace to form a layer of ZnO, which encapsulated the liquid Zn vapor. Zinc oxidizes as it travels though air, and, depending on its trajetory, a variety of morphologies. The dynamic system was based on a quartz tube reactor seled at both ends and with controlled injection of argon and oxygen while the process takes place at 900 C. One dominant structure is in the form of tetrapods whose ends form the apices of regular tetrapodron, with dimensions ranging from a few hundred nanometers to several microns. The nature of these nanostructures was characterized by transmission electron microscopy (SEM and TEM) and their optical properties have been studied using and cathodoluminescence. Images show that the UV emission originates bulk of the legs, while the green emission emanates from the surface, indicative of it being related to oxygen vacancies.

ASSUNTO(S)

sintesis nanoestructure synthesis microscopia eletronica nanoestrutura microscopia eletronica propriedade luminescente nanoestructura electron microscopy luminescent propertie propriedade luminiscente sintese

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