Erbium Doped SiO2 Layers Formed on the Surface of Silicon by Spark Processing

We present structural and spectroscopic analyses of luminescent erbium-doped porous SiO2 layers on silicon formed using a spark processing technique. Scanning electron microscopy reveals a surface of irregular holes covered by a SiO2 layer. Concomitant energy-dispersive X-ray mapping experiments show that the erbium concentration in the porous layer can be controlled by varying the molarity of the erbium solution deposited on the substrate prior to spark processing. Both visible and near-infrared photoluminescence spectroscopy, under conditions of varying temperature and excitation power, have been used to study the nature of the erbium centers formed in the porous layer. Self-quenching of Er3+ photoluminescence at 1.54 μm occurs at the highest concentrations of erbium employed.