Publications by authors named "H Renevier"
Article Synopsis
- Conducted a quantitative analysis of X-ray absorption spectroscopy (XAS) during the growth of ultrathin titanium disulfide (TiS) films using a two-step process involving atomic layer deposition/molecular layer deposition (ALD/MLD) and subsequent annealing.
- This innovative approach separates growth and crystallization, initially producing an amorphous Ti-thiolate that transforms into crystalline TiS through thermal annealing.
- Findings reveal the bonding nature at the interface with the SiO substrate, the gradual incorporation of sulfur during the process, and highlight the critical role of the annealing step in inducing transformation and sulfur loss, thus supporting the effectiveness of the two-step synthesis method.
The selection of the polarity of ZnO nanowires grown by chemical bath deposition offers a great advantage for their integration into a wide variety of engineering devices. However, the nucleation process of ZnO nanowires and its dependence on their polarity is still unknown despite its importance for optimizing their morphology and properties and thus to enhance the related device performances. To tackle this major issue, we combine an analysis of the nucleation process of O- and Zn-polar ZnO nanowires on O- and Zn-polar ZnO single crystals, respectively, using synchrotron radiation-based grazing incidence X-ray diffraction with transmission and scanning electron microscopy.
View Article and Find Full Text PDFNanoscale x-ray investigation of composition fluctuations in AlGaN nanowires.
Nanotechnology
September 2020
In the present study we combined, in the same synchrotron x-ray experiment, reciprocal space mapping, multiwavelength anomalous diffraction and diffraction anomalous fine structure, to determine the strain, crystallographic polarity, alloy composition and ordering at the atomic scale in [0001]-oriented AlGaN nanowires grown by molecular beam epitaxy on GaN nanowire bases. The information that we obtained was averaged over a macroscopic ensemble of NWs. We found from the diffraction anomalous fine structure that there were an isotropic increased number of Ga-Ga pairs in the Ga next nearest coordination shell (cation sublattice) with respect to what is expected for the AlGaN alloy composition determined by anomalous diffraction.
View Article and Find Full Text PDFInGaAs is one of the III-V active semiconductors used in modern high-electron-mobility transistors or high-speed electronics. ZnO is a good candidate material to be inserted as a tunneling insulator layer at the metal-semiconductor junction. A key consideration in many modern devices is the atomic structure of the hetero-interface, which often ultimately governs the electronic or chemical process of interest.
View Article and Find Full Text PDFArticle Synopsis
- - The polarity of ZnO nanowires significantly impacts their properties and performance in nanoscale-engineering devices, making its measurement crucial yet challenging due to the complexity of the underlying polycrystalline ZnO seed layer.
- - By employing a combination of resonant x-ray diffraction, piezoelectric force microscopy, and polarity-sensitive chemical etching, researchers successfully analyzed the polarity of over 10 nanostructures on both macroscopic and microscopic levels.
- - High-temperature annealing revealed that the ZnO seed layer is predominantly Zn-polar (over 92%), which is also reflected in the polarity of the grown ZnO nanowires; this emphasizes the potential for creating unipolar nanowire arrays for specific applications like