Enhancement Of Fluorescence Based On Porous Silicon/Rare Earth Photonic Devices

Porous silicon(PS) is an excellent substrate material since it was be found in Bell Labs in 1956. The room-temperature photoluminescence(PL) of porous silicon was found in1990 by Canham which open up new field for the application of the porous silicon. However, the wide photoluminescence band(100 nm-150 nm) and low luminous efficiency of conventional structure porous silicon hinder the application of porous silicon in light-emitting devices field.Enhancing the photoluminescence of porous silicon in visible range by doping substance is widespread. The rare earth(RE) is a good candidate due to the abundant energy levels.In this paper, we combine the porous silicon which is made into photonic crystal structures with the rare earth and research the PL properties of porous silicon. The goal of improving PL properties of porous silicon is achieved. The work and conclusions of this paper is as follows:1. Macro-porous silicon is prepared by using electrochemical etch in n-type silicon(resistivity: 0.01-0.02 ??cm). The rare earth(Yb) which has no fluorescence in the visible range is doped into porous silicon by electrochemical deposition method and the doping time impact on fluorescence of porous silicon is researched. We found that the doping time 3 minutes is the best.2. The electrochemical etch method was used in p+-type silicon(resistivity: 0.03-0.06 ??cm) to prepare the porous silicon Bragg reflectors with a bandgap cover the PL band of porous silicon. The rare earth(Yb) was doped into porous silicon by electrochemical deposition method and the photoluminescence of porous silicon was researched. The goal of double enhance the PL of porous silicon by rare earth and Bragg structures is achieved.3. The electrochemical etch method was used in p+-type silicon(resistivity: 0.03-0.06 ??cm) to prepare the porous silicon microcavities which has the resonant cavity in the middle of the photoluminescence band of porous silicon. The rare earth(Yb) was doped into porous silicon by electrochemical deposition method and the photoluminescence of porous silicon was researched. We found that the rare earth(Yb) is doped into porous silicon with microcavity structures, which result in double enhancement of the porous silicon PL by photonic crystal and the rare earth, and narrowed the PL bandwidth of PSMs at the same time.