ENHANCEMENT AND STABILIZATION OF POROUS SILICON PHOTOLUMINESCENCE BY OXYGEN INCORPORATION WITH A REMOTE-PLASMA TREATMENT

We report a treatment that enhances and stabilizes the photoluminescence (PL) from porous Si films. Films prepared by anodization in a 50% HF/ethanol solution were annealed at 450-degrees-C in vacuum, exposed to air, and then exposed to a remote-hydrogen plasma. Infrared absorption spectroscopy revealed that the concentration of oxygen, rather than hydrogen, was increased by the processing steps, and that silicon dihydride species had been eliminated from the surface. The PL from a treated film was initially approximately 30 times more intense than from the as-etched films. The PL intensity increased with illumination time in air until a steady-state intensity was reached.