Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 40: Impurities / Amorphous Semiconductors
HL 40.6: Vortrag
Dienstag, 27. März 2012, 12:45–13:00, EW 015
THz spectroscopy of the 29 cm−1 oxygen vibrational line in natural silicon and isotopically enriched 28Si — •Kurt Lassmann1, Boris Gorshunov1,2,3, P.S. Korolev2,4, E.S. Zhukova1,2,3, V.P. Kalinsuhkin2, N.V. Abrosimov5, P.G. Sennikov6, H.-J. Pohl7, S. Zakel8, and Martin Dressel1 — 11. Phys. Inst., Univ. Stuttgart — 2A.M. Prokhorov Gen. Phys. Inst., RAS, Moscow — 3Moscow Inst. Physics and Technology — 4Lomonosov Moscow State Univ. — 5Leibniz Inst. Kristallzüchtung, Berlin — 6Inst. Chem. High-Purity Substances, Nizhny Nowgorod — 7PTB, Braunschweig — 8VITCON-Projektconsult, Jena
Looking for a possible host-isotope effect on the low-energy two-dimensional motion of interstitial oxygen in silicon we have measured the resonance parameters of the lowest transition of the 30 cm−1 band of the Si-O-Si complex in natural Si and in isotopically enriched 28Si at temperatures between 5 K and 22 K by means of coherent-source terahertz spectroscopy. At 5.5 K we obtain for the resonance maxima 29.24 ± 0.003 cm−1 and 29.22 ± 0.003 cm−1 and for the line widths 0.09 ± 0.01 cm−1 and 0.11 ± 0.01 cm−1 for 28Si and natSi, respectively. Both lines can be fitted by single Lorentzians, so, no obvious isotopic structure or asymmetry of the line in natSi due to the Si neighbors in the Si-O-Si complex is detected. We therefore conclude that down-shift and broadening of the natSi-resonance is not due to the Si isotopes in the isolated Si-O-Si complex but to an average effect of the isotopically inhomogeneous lattice.