Rachel S. Goldman

Professor

rsgold@umich.edu

2094 H.H. Dow Building

T: (734) 647-6821

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Structure-Property Correlations: Effects of Dislocations on Electron Mobility

Sponsor: National Science Foundation DMR-9773707, DMR-0210714
InSb films grown on GaAs exhibit a thickness-dependent electron mobility, which we determined to be due to scattering of free carriers from dislocations. Of particular importance in our work is that we showed that other factors, including surface and interface roughness, do not play a significant role in limiting the electron mobility of the films. In addition, we proved that it is the strain field associated with the dislocations, rather than the carrier depletion region surrounding them, which scatters the free carriers and limits the electron mobility (ref). We have recently completed a follow up investigation of the effects of various buffers on the electronic properties of n-type InSb films, showing that ionized impurity scattering competes with the scattering associated with the dislocation strain fields (ref). One of our long-term interests is to develop more sophisticated models to explain and predict the effects of dislocations on the properties of a variety of heteroepitaxial films.
Highlights (Click an image for more information)
  • Dislocation Engineering of InSb Films

    TEM image showing threading dislocations in an InSb film grown on a GaAs substrate. The free carrier scattering from the lattice dilation associated with threading dislocations, rather then scattering from a depletion potential surrounding the dislocations, is the dominant factor limiting the electron mobility in the InSb film.