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HL: Fachverband Halbleiterphysik
HL 74: Group IV: Si/Ge/SiC
HL 74.4: Vortrag
Donnerstag, 23. März 2017, 12:45–13:00, POT 06
Direct band gap and strain-related properties of germanium under high uniaxial stress — •Kevin Guilloy1, Alban Gassenq1, Nicolas Pauc1, S. Tardif1, F. Rieutord1, Y.M. Niquet1, J.M. Escalante1, I. Duchemin1, L. Milord2, G. Osvaldo Dias2, D. Rouchon2, J. Widiez2, J.M. Hartmann2, J. Aubin2, A. Chelnokov2, R. Geiger3, T. Zabel3, E. Marin3, H. Sigg3, J. Faist4, V. Reboud2, and Vincent Calvo1 — 1Université Grenoble Alpes, CEA-INAC, Grenoble, France — 2Université Grenoble Alpes, CEA-LETI Minatec, Grenoble, France — 3Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, Villigen, Switzerland — 4Institute for Quantum Electronic, ETH Zurich, Switzerland
The induction of high tensile strain is predicted to make germanium a direct band gap semiconductor. We present here an experimental study of the dependence of such a tensile stress on the direct optical transitions and the Raman strain-induced shift.
Using germanium-on-insulator (GeOI) substrates, we fabricated micro-membranes amplifying the residual stress of the germanium layer. Laue X-ray diffraction measurements at the BM32 beamline (ESRF) showed the strain reaches 4.9 %. We studied the relationship between the strain measured by XRD and the Raman shift and observed a unexpected nonlinear behaviour.
We finally performed electro-absorption spectroscopy on micro-bridges to determine the energy of its optical transitions, showing that the relation between strain and the energy of these transitions differs significantly from previous models.