Heteroepitaxial devitrification of silica to integrate functional oxide nanostructures on silicon
Résumé
The integration of quartz on silicon in thin film form is a challenging issue due to the differences in the crystal structures of these materials. In this regard, this work overcomes the main challenges for the integration of novel functional oxide materials on silicon including (i) epitaxial piezoelectric α-quartz thin films [1] and (ii) 1D single crystalline phases of manganese oxides that share common growth mechanisms [2,3]. The aim of this contribution is to discuss in detail the non classical nucleation and crystallization mechanisms of these materials grown from chemical solutions. Quartz films are crystallized by a confined devitrification of amorphous silica films assisted by a heterogeneous catalysis driven by alkaline earth cations present in the precursor solution. The films are made of perfectly oriented individual crystallites epitaxially grown on (100)-Si. The active influence of the Si substrate mediates the preferential orientation of crystal nuclei, yielding competitive growth and producing a columnar microstructure. Quartz films are piezoelectric and can be used as template for the epitaxial growth of manganese oxide nanowires on silicon. This methodology exhibits a great potential for the design of novel oxide compounds on silicon with unique properties. [1]A. Carretero-Genevrier et al. Science 340, 827 (2013) [2]A. Carretero-Genevrier et al. Chem.Mater. 10.1021/cm403064u (2013) [3]A. Carretero-Genevrier et al. Chem.Soc.Rev. 10.1039/C3CS60288E (2013)