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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 18, Iss. 25 — Dec. 6, 2010
  • pp: 25596–25607

Measurement and modeling of ultrafast carrier dynamics and transport in germanium/silicon-germanium quantum wells

Stephanie A. Claussen, Emel Tasyurek, Jonathan E. Roth, and David A. B. Miller  »View Author Affiliations

Optics Express, Vol. 18, Issue 25, pp. 25596-25607 (2010)

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We measure the intervalley scattering time of electrons in the conduction band of Ge quantum wells from the direct Γ valley to the indirect L valley to be ~185 fs using a pump-probe setup at 1570 nm. We relate this to the width of the exciton peak seen in the absorption spectra of this material, and show that these quantum wells could be used as a fast saturable absorber with a saturation fluence between 0.11 and 0.27 pJ/μm2. We also observe field screening by photogenerated carriers in the material on longer timescales. We model this field screening by incorporating carrier escape from the quantum wells, drift across the intrinsic region, and recovery of the applied voltage through diffusive conduction.

© 2010 OSA

OCIS Codes
(200.4650) Optics in computing : Optical interconnects
(230.0250) Optical devices : Optoelectronics
(230.5590) Optical devices : Quantum-well, -wire and -dot devices
(320.2250) Ultrafast optics : Femtosecond phenomena
(230.4205) Optical devices : Multiple quantum well (MQW) modulators

ToC Category:
Ultrafast Optics

Original Manuscript: October 4, 2010
Revised Manuscript: November 11, 2010
Manuscript Accepted: November 14, 2010
Published: November 22, 2010

Stephanie A. Claussen, Emel Tasyurek, Jonathan E. Roth, and David A. B. Miller, "Measurement and modeling of ultrafast carrier dynamics and transport in germanium/silicon-germanium quantum wells," Opt. Express 18, 25596-25607 (2010)

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  1. Y.-H. Kuo, Y. K. Lee, Y. Ge, S. Ren, J. E. Roth, T. I. Kamins, D. A. B. Miller, and J. S. Harris., “Quantum-Confined Stark Effect in Ge/SiGe Quantum Wells on Si for Optical Modulators,” IEEE J. Sel. Top. Quantum Electron. 12(6), 1503–1513 (2006). [CrossRef]
  2. J. E. Roth, O. Fidaner, R. K. Schaevitz, Y.-H. Kuo, T. I. Kamins, J. S. Harris, and D. A. B. Miller, “Optical modulator on silicon employing germanium quantum wells,” Opt. Express 15(9), 5851–5859 (2007), http://www.opticsinfobase.org/abstract.cfm?URI=oe-15-9-5851 . [CrossRef] [PubMed]
  3. J. E. Roth, O. Fidaner, E. H. Edwards, R. K. Schaevitz, Y.-H. Kuo, N. C. Helman, T. I. Kamins, J. S. Harris, and D. A. B. Miller, “C-band side-entry Ge quantum-well electroabsorption modulator on SOI operating at 1 V swing,” Electron. Lett. 44(1), 49–50 (2008). [CrossRef]
  4. J. Shah, Ultrafast Spectroscopy of Semiconductors and Semiconductor Nanostructures (Springer-Verlag, Berlin, 1999).
  5. G. Mak and H. M. van Driel, “Femtosecond transmission spectroscopy at the direct band edge of germanium,” Phys. Rev. B Condens. Matter 49(23), 16817–16820 (1994). [CrossRef] [PubMed]
  6. X. Zhou, H. van Driel, and G. Mak, “Femtosecond kinetics of photoexcited carriers in germanium,” Phys. Rev. B Condens. Matter 50(8), 5226–5230 (1994). [CrossRef] [PubMed]
  7. C. Lange, N. S. Koster, S. Chatterjee, H. Sigg, D. Chrastina, G. Isella, H. von Kanel, B. Kunert, and W. Stolz, “Comparison of ultrafast carrier thermalization in GaxIn1-xAs and Ge quantum wells,” Phys. Rev. B 81(4), 045320 (2010). [CrossRef]
  8. S. Claussen, L. Tang, J. Roth, O. Fidaner, S. Latif, and D. A. B. Miller, “Femtosecond carrier dynamics in Ge/SiGe quantum wells,” presented at the 4th International Conference on Group IV Photonics, Tokyo, Japan, 19–21 Sept. 2007.
  9. J. A. Cavaillès, D. A. B. Miller, J. E. Cunningham, P. L. Kam Wa, and A. Miller, “Simultaneous measurement of electron and hole escape times from biased single quantum wells,” Appl. Phys. Lett. 61(4), 426–428 (1992). [CrossRef]
  10. G. Livescu, D. A. B. Miller, T. Sizer, D. J. Burrows, J. Cunningham, A. C. Gossard, and J. H. English, “High-speed absorption recovery in quantum well diodes by diffusive electrical conduction,” Appl. Phys. Lett. 54(8), 748–750 (1989). [CrossRef]
  11. M. B. Yairi and D. A. B. Miller, “Equivalence of diffusive conduction and giant ambipolar diffusion,” J. Appl. Phys. 91(7), 4374–4381 (2002). [CrossRef]
  12. H. S. Wang, F. J. Effenberger, P. LiKamWa, and A. Miller, “Ultrafast cross-well carrier transport in a strained multiple-quantum-well InGaAs-GaAs p-i-n modulator,” IEEE J. Quantum Electron. 33(2), 192–197 (1997). [CrossRef]
  13. R. K. Schaevitz, J. E. Roth, S. Ren, O. Fidaner, and D. A. B. Miller, “Material Properties in Si-Ge/Ge Quantum Wells,” IEEE J. Sel. Top. Quantum Electron. 14(4), 1082–1089 (2008). [CrossRef]
  14. D. T. Reid, “Measuring ultra fast laser pulses,” in Ultrafast Photonics, A. Miller, D.T. Reid, and D.M. Finlayson, ed. (Bristol and Philadelphia: Scottish Universities Summer School in Physics and Institute of Physics Publishing, 2002).
  15. A. Othonos, “Probing ultrafast carrier and phonon dynamics in semiconductors,” J. Appl. Phys. 83(4), 1789–1830 (1998). [CrossRef]
  16. M. V. Lebedev, O. V. Misochko, T. Dekorsy, and N. Georgiev, “On the nature of “coherent artifact”,” J. Exp. Theor. Phys. 100(2), 272–282 (2005). [CrossRef]
  17. A. E. Siegman, M. W. Sasnett, and T. F. Johnston, “Choice of Clip Levels for Beam Width Measurements Using Knife-Edge Techniques,” IEEE J. Quantum Electron. 27(4), 1098–1104 (1991). [CrossRef]
  18. E. R. Brown, D. C. Driscoll, and A. C. Gossard, “State-of-the-art in 1.55 μm ultrafast InGaAs photoconductors, and the use of signal processing techniques to extract the photocarrier lifetime,” Semicond. Sci. Technol. 20(7), 199–204 (2005). [CrossRef]
  19. D. S. Chemla, D. A. B. Miller, P. W. Smith, A. C. Gossard, and W. Wiegmann, “Room Temperature Excitonic Nonlinear Absorption and Refraction in GaAs/AlGaAs Multiple Quantum Well Structures,” IEEE J. Quantum Electron. 20(3), 265–275 (1984). [CrossRef]
  20. E. H. Edwards, R. M. Audet, Y. Rong, S. A. Claussen, R. K. Schaevitz, E. Tasyürek, S. Ren, and I. Ted, Kamins, O. I. Dosunmu, M. S. Ünlu, J. S. Harris, and D. A. B. Miller, “Si-Ge Surface-normal Asymmetric Fabry-Perot Quantum-confined Stark Effect Electroabsorption Modulator,” presented at the IEEE Annual Photonics Society Meeting, Denver, CO, 7–11 Nov. 2010.
  21. P. Chaisakul, D. Marris-Morini, G. Isella, D. Chrastina, X. Le Roux, E. Gatti, S. Edmond, J. Osmond, E. Cassan, and L. Vivien, “Quantum-confined Stark effect measurements in Ge/SiGe quantum-well structures,” Opt. Lett. 35(17), 2913–2915 (2010). [CrossRef] [PubMed]
  22. J. Roth, “Electroabsorption Modulators for CMOS Compatible Optical Interconnects in III-V and Group IV Materials,” Stanford University Electrical Engineering Ph.D. Dissertation, August 2007.
  23. F. J. Grawert, J. T. Gopinath, F. Ö. Ilday, H. M. Shen, E. P. Ippen, F. X. Kärtner, S. Akiyama, J. Liu, K. Wada, and L. C. Kimerling, “220-fs erbium-ytterbium:glass laser mode locked by a broadband low-loss silicon/germanium saturable absorber,” Opt. Lett. 30(3), 329–331 (2005). [CrossRef] [PubMed]
  24. Y. Silberberg, P. W. Smith, D. J. Eilenberger, D. A. B. Miller, A. C. Gossard, and W. Wiegmann, “Passive mode locking of a semiconductor diode laser,” Opt. Lett. 9(11), 507–509 (1984). [CrossRef] [PubMed]
  25. U. Keller, D. A. B. Miller, G. D. Boyd, T. H. Chiu, J. F. Ferguson, and M. T. Asom, “Solid-state low-loss intracavity saturable absorber for Nd:YLF lasers: an antiresonant semiconductor Fabry-Perot saturable absorber,” Opt. Lett. 17(7), 505–507 (1992). [CrossRef] [PubMed]
  26. M. A. Omar and L. Reggiani, “Drift velocity and diffusivity of hot carriers in germanium: model calculations,” Solid-State Electron. 30(12), 1351–1354 (1987). [CrossRef]

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