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Substrate Symmetry Driven Endotaxial Silver Nanostructures by Physical and Chemical Vapor Deposition Methods

Lundi 29 avril 2013 14:00 - Duree : 1 heure
Lieu : Room 500 - 501, Central Building, ESRF - 6 Rue Jules Horowitz - Grenoble

Orateur : P. V. SATYAM (Institute of Physics Bhubaneswar, India)

We report a novel method of growth for endotaxial silver nano squares/rectangles, nanorods and nano triangles on Si (100), Si (110), Si (111) substrates corresponding to their 4, 2, and 3-fold substrate symmetries, respectively. Our procedure involves a phenomenon of low temperature thermal etching of native oxide on silicon substrate using GeOx layer as an etchant to grow substrate symmetry driven endotaxial nano structures in the atmospheric pressure Chemical Vapor Deposition (CVD) system. We report on procedures to tune the shape, size and placement of the silver nanostructures by using the parameters such as substrate orientation, temperature and time of deposition during the CVD growth. A very detailed planar and cross-sectional high resolution electron microscopy study is presented to elucidate the growth mechanism of these interesting structures. In case of silver film deposition using physical vapor deposition, Depending on the configuration of a thin GeOx film and a thin Ag film on silicon wafers with (100), (110) and (111) orientations, and upon annealing in air at high temperatures, nanostructures of Ag or AgxSiy were formed with square, rectangular and triangular shapes for resulting nanostructures, respectively. With a thin GeOx layer sandwiched between substrate silicon surface (with native oxide) and an Ag thin film, annealing at ≈ 800 °C has resulted in endotaxial single crystalline Ag nanostructures of shapes depending on symmetry of the substrate orientation. When the configuration exchanged between GeOx and Ag films (i.e., with the deposition GeOx film on top of Ag film), embedded Ag nanostructures (within the GeOx film) of spherical shape were observed. Interestingly, direct deposition of Ag thin films on native oxide covered silicon substrate, without any GeOx thin films at the interface, resulted in endotaxial AgxSiy nanostructures. [1] R. R. Juluri, A. K. Rath, A. Ghosh and P. V. Satyam, Under Review (2013)

Contact : zegenhag@esrf.fr

Discipline évènement : (Physique)
Entité organisatrice : (ESRF)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire ESRF)
Site de l'évènement : Polygone scientifique

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