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APS » Journals » Phys. Rev. B » Volume 78 » Issue 4
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Phys. Rev. B 78, 041407(R) (2008) [4 pages]

Optical transitions in Ge/SiGe multiple quantum wells with Ge-rich barriers

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M. Bonfanti, E. Grilli, and M. Guzzi
CNISM and L-NESS, Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via Cozzi 53, I-20125 Milano, Italy

M. Virgilio and G. Grosso
NEST-INFM, Piazza San Silvestro 12, 5612 Pisa, Italy and Dipartimento di Fisica “E. Fermi,” Università di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy

D. Chrastina, G. Isella, and H. von Känel
CNISM and L-NESS, Dipartimento di Fisica del Politecnico di Milano, Polo di Como, Via Anzani 42, I-22100 Como, Italy

A. Neels
Institute of Microtechnology, University of Neuchâtel, Rue Jaquet-Droz 1, CH-2002 Neuchâtel, Switzerland

Received 25 June 2008; published 25 July 2008

Direct-gap and indirect-gap transitions in strain-compensated Ge/SiGe multiple quantum wells with Ge-rich SiGe barriers have been studied by optical transmission spectroscopy and photoluminescence experiments. An sp3d5s∗ tight-binding model has been adopted to interpret the experimental results. Photoluminescence spectra and their comparison with theoretical calculations prove the existence of type-I band alignment in compressively strained Ge quantum wells grown on relaxed Ge-rich SiGe buffers. The high quality of the transmission spectra opens up other perspectives for application of these structures in near-infrared optical modulators.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.78.041407
DOI:
10.1103/PhysRevB.78.041407
PACS:
78.67.De, 73.21.Fg
 
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