Porous silicon optical microcavity for chemical sensing application using tris-(8-hydroxyquinoline) aluminum (Alq3)

The present paper reports the study of a porous silicon based microcavity for a potential chemical sensing application using tris-(8-hydroxyquinoline) aluminum (Alq 3 ) molecules. Porous silicon based planar microcavity was first designed and fabricated using the electrochemical etching technique. Photoluminescence emission of a single porous silicon layer after immersion in an Alq 3 solution was first carried out in order to verify that the Alq 3 molecules were bound to the porous surface. A wide green band centered at 519 nm, typical of a nano-structured Alq 3 film, was observed. Reflectivity measurements of the porous silicon microcavity were then performed for different aluminum concentrations of the Alq 3 solution. The microcavity device showed a good sensibility for the Alq 3 molecules and an important shift of the microcavity photonic resonance was observed. This device might be considered for a potential aluminiun sensing application.