Quantum interference in the n-channel of a Si:SiGe quantum well

R. S. Prasad, T. J. Thornton, A. Matsumura, J. M. Fernandez, D. Williams

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


We have grown n-channel Si:SiGe quantum wells using gas source molecular beam epitaxy. The two-dimensional electron gas confined in the strained Si quantum well is weakly disordered and displays quantum interference in the form of a pronounced, low-field negative magnetoresistance. By fitting the data to the standard theory of weak localization, in the temperature range 50 mK to 6 K, we have been able to extract the product Nv alpha and the electron phase coherence length Lphi. Our results give a value for the product Nv alpha in the range 0.6+or-0.12, which is close to that expected for strong intervalley scattering and is similar to values obtained in Si MOSFETs. We show a power law dependence of Lphi with temperature, i.e. Lphi varies as T-p2/. For T>0.7 K the value of the exponent p/2=0.75 which suggests that the dominant dephasing mechanism is electron-phonon scattering as observed in Si MOSFETs. However, for lower temperatures the variation is less pronounced (p/2=0.15). The weaker temperature dependence may be a precursor to a saturation in the value of Lphi as has recently been observed by other groups.

Original languageEnglish (US)
Article number005
Pages (from-to)1084-1088
Number of pages5
JournalSemiconductor Science and Technology
Issue number8
StatePublished - Dec 1 1995
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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