Effect of hydrogen passivation on luminescence-center-mediated Er excitation in Si-rich SiO(2) with and without Si nanocrystals

    Authors

    O. Savchyn; P. G. Kik; R. M. Todi;K. R. Coffey

    Comments

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    Abbreviated Journal Title

    Phys. Rev. B

    Keywords

    ELECTRON-PARAMAGNETIC-RESONANCE; IMPLANTED SILICA GLASS; ENERGY-TRANSFER; OPTICAL-PROPERTIES; DOPED SIO2; POROUS SILICON; QUANTUM; DOTS; SURFACE PASSIVATION; SI-SIO2 INTERFACE; SPIN-RESONANCE; Physics, Condensed Matter

    Abstract

    The influence of hydrogen passivation on luminescence-center-mediated excitation of Er(3+) in Er-doped Si-rich SiO(2) films with significantly different microstructures is studied. Photoluminescence measurements are presented for samples containing no detectable silicon nanocrystals (annealed at 600 degrees C) and for samples containing silicon nanocrystals (annealed at 1100 degrees C) as a function of hydrogen passivation temperature. Passivation is found to have little effect on the Er(3+) photoluminescence intensity at 1535 nm in the samples that do not contain nanocrystals. In contrast, a pronounced increase in the Er3+ photoluminescence intensity is observed in the samples containing Si nanocrystals, which is accompanied by a similar increase in the nanocrystal photoluminescence intensity and a gradual increase in the Si nanocrystal emission lifetime. This observation is attributed to two interrelated effects, namely, (a) an increase in the density of fully passivated optically active nanocrystals due to the passivation-induced removal of silicon dangling bonds and (b) a concurrent reduction in nonradiative Er(3+) relaxation from levels above the (4)I(13/2) level due to a direct interaction of excited Er(3+) ions with silicon dangling bonds. In addition, the observed counterintuitive gradual increase in the nanocrystal photoluminescence decay time upon passivation is successfully explained taking into account a passivation-induced change in the concentration of optically active nanocrystals with different sizes and the inhomogeneous nature of the nanocrystal-related emission band. It is shown that the combination of luminescence-center-mediated Er(3+) excitation and silicon-dangling-bond-induced Er(3+) de-excitation can explain at least 14 experimental observations reported by independent authors.

    Journal Title

    Physical Review B

    Volume

    77

    Issue/Number

    20

    Publication Date

    1-1-2008

    Document Type

    Article

    Language

    English

    First Page

    11

    WOS Identifier

    WOS:000256971800124

    ISSN

    1098-0121

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