Enhanced band-gap luminescence in strain-symmetrized (Si)m(Ge)n superlattices

U. Menczigar, G. Abstreiter, H. Kibbel, H. Presting, E. Kasper

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

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We report on band-gap luminescence in short period, strain-symmetrized (Si)m(Ge)n superlattices grown on relaxed, step-graded Si1-xGex alloy buffer layers. The dislocation density in the superlattices, which were grown at 500°C using Sb as a surfactant, is reduced by 2-3 orders of magnitude compared with superlattices grown on thin, partly relaxed Si1-xGex buffer layers. Due to the improved quality of the superlattices, well defined band-gap luminescence could be observed which is for a (Si)6(Ge)4 superlattice strongly enhanced compared with a Si0.6Ge0.4 alloy reference sample. The measured band-gap energies compare well with theoretical predictions. To study the influence of interdiffusion of the Si- and Ge-layers on the band-gap of the superlattices, the samples were annealed and studied with photoluminescence and Raman spectroscopy. An increasing band-gap and a decreasing luminescence efficiency was found with increasing intermixing of the layers. These experimental results are well described with an interdiffusion model of the layers in conjunction with an effective mass calculation.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium Proceedings
PublisherPubl by Materials Research Society
Number of pages12
ISBN (Print)1558991948, 9781558991941
StatePublished - 1993
EventProceedings of the Symposium on Silicon-Based Optoelectronic Materials - San Francisco, CA, USA
Duration: 12 Apr 199314 Apr 1993

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


ConferenceProceedings of the Symposium on Silicon-Based Optoelectronic Materials
CitySan Francisco, CA, USA


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