The processes of erbium impurity excitation in Si/Si1−xGex:Er/Si heteroepitaxial structures

•Er doped Si/Si1−xGex/Si heterostructures have been prepared and characterized.•Luminescence, photoconductivity, PL excitation studies have been performed.•Erbium PL has been observed both under band-to-band and sub-bandgap excitation.•Excitation efficiency of Er ions has been investigated. We repor...

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Bibliographic Details
Published in:Optical materials 2013-05, Vol.35 (7), p.1404-1409
Main Authors: Krasilnikova, L.V., Stepikhova, M.V., Antonov, A.V., Shengurov, V.G., Krasilnik, Z.F.
Format: Article
Language:English
Subjects:
Backscattering
Banded structure
Cross sections
Erbium
Excitation
Heterostructures
Impurities
Molecular beam epitaxy
Photoluminescence spectroscopy
Semiconductors
Silicon
Solid solutions
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Summary:•Er doped Si/Si1−xGex/Si heterostructures have been prepared and characterized.•Luminescence, photoconductivity, PL excitation studies have been performed.•Erbium PL has been observed both under band-to-band and sub-bandgap excitation.•Excitation efficiency of Er ions has been investigated. We report a study into the photoluminescence excitation spectra of Er3+ ions in Si/Si1−xGex:Er/Si heteroepitaxial structures containing 10–31% germanium. The structures of this type are of interest for a laser realization on Si basis. It is shown that a characteristic maximum in the 1040–1050nm region that appears in these structures is related with the backscattering effects of radiation in the silicon substrate. The excitation efficiency of Er impurity in Si/Si1−xGex:Er/Si structures is investigated in conditions of band-to-band and sub-bandgap optical pumping with the photon energies smaller than the bandgap of a Si1−xGex solid solution. The effective excitation cross-section of erbium ions is shown to depend on the excitation mechanism, the excitation energy, and the parameters of Si1−xGex:Er layers. The values of the effective excitation cross-section of Er3+ ions in Si/Si1−xGex:Er/Si structures were found to vary from 4×10−15 to 0.5×10−16cm2 at T=77K. These values are comparable with the highest values obtained for the excitation cross-section of Er3+ ions in silicon and exceed by several orders of magnitude the effective cross-section of Er3+ ions under direct (intra-atomic) excitation.
ISSN:0925-3467
1873-1252
DOI:10.1016/j.optmat.2013.02.015