This work describes the infiltration of a polymeric solution into porous Si structures towards the fabrication of
tunable photonic crystals (PC) and microcavities for photonics applications. The tunability is achieved by infiltrating the
porous silicon based PCs by active organic materials, such as an emissive and nonlinear polymer called 2-methoxy-5-(2-
ethylhexyloxy)-p-phenylenevinylene (namely MEH-PPV). This preliminary work shows the infiltration of this polymeric
solution into PC based on macroporous Si structure as well as in microcavities based on multiple layers of microporous
Si. The solidification of the polymer was obtained by the evaporation of the solvent. Various techniques of infiltration
were studied to obtain an optimized filling of the pores. The infiltration was then characterized using photoluminescence
measurements. Finally, we will report on the study of third harmonic generation (THG) in samples of porous silicon
microcavity infiltrated with MEHPPV. The k-domain THG spectroscopy was applied and an increase of the THG
intensity up to an order of magnitude was achieved for the filled microcavity.
We report here on the results of the characterization of a novel -OPhCN substituted thiophenic monomer, and of the obtained copolymers between the latter and the plastifying comonomer 3-hexylthiophene. The polymer evidences an excellent filmability from various organic solvents as well as an enhanced photoluminescence. The characteristics of the polymer were characterized by FTIR and XRD as well as photoluminescence. A bandgap of 2.0eV was obtained which corresponds to orange emission. Furthermore, a single layer organic device was fabricated and resulted in bright stable electroluminescence at room temperature. All of the results indicate that this polymer is a promising emissive material for application in light-emitting devices (LEDs).
Macroporous silicon structures have been fabricated by electrochemical etching. Such fabrication process is known to result in the presence of a thin microporous Si layer at the walls of the macropores and at the surface. Photoluminescence measurements conducted in plan-view and cross-section exhibit a wide emission peak around 650nm which can be attributed to the microporous Si. The combination of a photonic crystal and a light emitter in one structure represents a potential for applications that has not been studied previously. This preliminary study shows the influence of the main fabrication parameters, namely the current density and the etchant solution, on the emission properties of the microporous Si layer.