Microstructure, chimie et propriétés optiques de films minces ZnO et nanocomposites ZnO-Au synthétisés par pulvérisation cathodique magnétron réactive

Abstract : Composite materials can exhibit properties that none of the individual components show. Moreover, composites at the nanoscale can present new properties compared to the bulk state or to macro-composites due to confinement and quantum size effects. The semiconductor/metal nanocomposites are highly interesting due to their unique catalytic and optoelectronic properties and the possibility to tune them easily. This PhD work gives insight into the specific interactions and resulting physical properties occurring in ZnO and ZnO-Au nanocomposite films grown by reactive DC magnetron sputtering. The results can be summarized in two points: First, it was possible to tune the microstructural and optical properties of ZnO. Epitaxial growth of ZnO onto sapphire was achieved for the first time in O2-rich conditions without thermal assistance. Also, a study of the optical properties highlights the close relationship between the bandgap energy (E_g ) and the defect chemistry in ZnO films. A model was proposed to explain the large scatter of the E_g values reported in the literature. Second, the deep influence of the incorporation of gold into the ZnO matrix on important material properties was revealed. Moreover, the presence of donor (acceptor) defects in the matrix is found to give rise to the reduction (oxidation) of the Au nanoparticles. This research work contributes to a better understanding of semiconductor/metal nanocomposites revealing the key role of the state of the semiconductor matrix
Document type :
Theses
File URL :
http://docnum.univ-lorraine.fr/prive/DDOC_T_2014_0253_CHAMORRO_CORAL.pdf
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https://hal.univ-lorraine.fr/tel-01751375
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Submitted on : Thursday, March 29, 2018 - 1:17:58 PM
Last modification on : Wednesday, September 4, 2019 - 2:06:03 PM

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  • HAL Id : tel-01751375, version 1

Citation

William Chamorro Coral. Microstructure, chimie et propriétés optiques de films minces ZnO et nanocomposites ZnO-Au synthétisés par pulvérisation cathodique magnétron réactive. Other. Université de Lorraine, 2014. English. ⟨NNT : 2014LORR0253⟩. ⟨tel-01751375⟩

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