Impact on timing and light extraction of a photonic crystal as measured on a half patterned LYSO crystal: implications for time of flight PET imaging

International audienc

In situ monitoring of thin alumina passive film growth by surface plasmon resonance (SPR) during an electrochemical process

International audienceAbstract This article presents a sensing technique to characterize the growth of an alumina passive film on an aluminum micro structured layer in situ. The technique uses surface plasmon resonance (SPR) on aluminum coated gratings with spectroscopic measurements during electrochemical polarization in 0.02M Na 2 SO 4 . The structure of the sensor was first simulated and then fabricated by photolithography. The grating was then replicated by nanoimprint (NIL) in Sol–Gel before pure aluminum layer was deposited by RF magnetron sputtering to produce the samples used in this study. Coupled plasmonic and electrochemical measurements confirmed the feasibility of in situ characterization (thickness) of alumina passive film on aluminum-based gratings in neutral aqueous media. Combining both measurements with an appropriated SPR spectrum fitting lead to alumina thickness monitoring within a few nanometers’ accuracy. The objectives and challenges of this study are to better characterize the alumina growth during electrochemical process combining in situ electrochemical process and SPR spectra in order to determine thin passive layer characteristics

HETONAN project: high efficiency tandem solar cells based on III-V nanowires on silicon

session: Dispositifs pour l'OptoélectroniqueNational audienc

HETONAN project: high efficiency tandem solar cells based on III-V nanowires on silicon

session: Dispositifs pour l'OptoélectroniqueNational audienc

ZnO homoepitaxy on the O polar face of hydrothermal and melt-growth substrates by pulsed laser deposition

2 cm diameter hydrothermal ZnO crystals were grown and then made into substrates using both mechanical and chemical-mechanical polishing (CMP). CMP polishing showed superior results with an (0002) Ω scan full width half maximum (FWHM) of 67 arcsec and an root mean square (RMS) roughness of 2 Å. In comparison, commercial melt-grown substrates exhibited broader X-ray diffraction (XRD) linewidths with evidence of sub-surface crystal damage due to polishing, including a downward shift of c-lattice parameter..