Papers by Author: Benjamin Dierre

Abstract: Beta-sialon:Eu²⁺ phosphor deposits were fabricated by electrophoretic deposition (EPD) process within a strong magnetic field (12 T). The direction of the magnetic field was adjusted to be parallel or perpendicular to that of the electric field, that is, vertical-or horizontal setup. The oriented deposits were fabricated by aligning the β-sialon:Eu²⁺ particles along the higher magnetic-susceptibility c-crystal axis (a, b-crystal plane). For the case of vertically-setup magnetic field, the oriented deposit aligned along the c-axis possessed higher relative deposit density than the randomly fabricated deposit, as a result, varying the intensity ratio of emission and transmitted excitation, and therefore, presenting different chromaticity coordinates; for the case of horizontally-setup magnetic field, photoluminescence (PL) intensities of the deposits oriented along c-axis were significantly improved by comparing with those of the randomly-oriented ones.

Abstract: In this work we report the enhancement of the 3C-SiC band edge luminescence induced by the SiO2 shell in SiC/SiO2 core/shell nanowires (NWs) system. We demonstrate that the shell enhances the SiC near band edge luminescence and we argue the formation of a type-I quantum well between the SiC core and the SiO2 shell, with the consequent injection of carriers from the larger band-gap shell to the narrower band-gap core.

Abstract: This study focus on the nature of different Si-based sensitizers for Er³⁺ ions in Silicon- Rich Silicon oxide thin films. The samples were first analyzed by Cathodoluminescence technique to probe all emitting centers in the films. Some of these centers were found to be potential sensitizers for Er³⁺ ions, such as Silicon Oxygen Deficient Center and Non-Bridging Oxygen Hole Center, in addition to the well-known Silicon-nanoclusters (Si-nc). The influence of the thickness was subsequently examined, revealing that the formation of Si-nc is inhibited for films thinner than 100 nm and this led to less sensitization of the Er³⁺ ions. We demonstrate that the introduction of a SiO₂ buffer layer can overcome this issue and increase the luminescence of Er³⁺ ions by a factor of five for films thinner than 50 nm that are usually used for electrically-driven photonic devices.