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Integration of III/V Semiconductors on Si and Ge

The integration of III/V semiconductors on Silicon or Germanium substrates has many novel applications in solar cells, LASERs as well as transistors. Moreover, the III/V on Si or Ge interface is also interesting fundamentally, as an unpolar material meets with a polar material. We investigate the intrinsic structure of the interface as well as of defects, like antiphase boundaries, arising at the interface. The figure shows an antiphase boundary in GaP from the top. Images like this can be quantitatively evaluated to get a 3-dimensional tomogram of this defect. At the interface as well as at defects wrong bonds, which result in a charge distribution deviating from the one of a perfect crystal, can occur. We also aim in developing STEM-based techniques to image this charge distribution with the use of pixelated detectors.