TY - GEN
T1 - Enhanced band-gap luminescence in strain-symmetrized (Si)m(Ge)n superlattices
AU - Menczigar, U.
AU - Abstreiter, G.
AU - Kibbel, H.
AU - Presting, H.
AU - Kasper, E.
PY - 1993
Y1 - 1993
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0027802397&partnerID=8YFLogxK
U2 - 10.1557/proc-298-33
DO - 10.1557/proc-298-33
M3 - Conference contribution
AN - SCOPUS:0027802397
SN - 1558991948
SN - 9781558991941
T3 - Materials Research Society Symposium Proceedings
SP - 33
EP - 44
BT - Materials Research Society Symposium Proceedings
PB - Publ by Materials Research Society
T2 - Proceedings of the Symposium on Silicon-Based Optoelectronic Materials
Y2 - 12 April 1993 through 14 April 1993
ER -