Title

Effect Of Hydrogen Passivation On Luminescence-Center-Mediated Er Excitation In Si-Rich Sio2 With And Without Si Nanocrystals

Abstract

The influence of hydrogen passivation on luminescence-center-mediated excitation of Er3+ in Er-doped Si-rich SiO2 films with significantly different microstructures is studied. Photoluminescence measurements are presented for samples containing no detectable silicon nanocrystals (annealed at 600°C) and for samples containing silicon nanocrystals (annealed at 1100°C) as a function of hydrogen passivation temperature. Passivation is found to have little effect on the Er3+ 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 Er3+ relaxation from levels above the I4 13/2 level due to a direct interaction of excited Er3+ 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 Er3+ excitation and silicon-dangling-bond-induced Er3+ de-excitation can explain at least 14 experimental observations reported by independent authors. © 2008 The American Physical Society.

Publication Date

5-30-2008

Publication Title

Physical Review B - Condensed Matter and Materials Physics

Volume

77

Issue

20

Number of Pages

-

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1103/PhysRevB.77.205438

Socpus ID

44449121405 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/44449121405

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