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Keywords:

  • InN films;
  • MBE;
  • Si doping;
  • positron annihilation;
  • vacancy formation

Abstract

The introduction of vacancy type point defects by Si doping in InN grown by plasma-assisted molecular beam epitaxy was studied using a monoenergetic positron beam. With the combination of positron lifetime and Doppler broadening measurements, compensating In-vacancy (VIn) acceptors were identified in the material. For increasing Si doping an enhanced formation of VIn defects was observed, up to a concentration of equation image in the highest doped sample (equation image). A strong inhomogeneity of the defect profile with a significant increase of the VIn concentration toward the layer/substrate interface could be detected. Additionally, larger vacancy clusters containing several VIn are formed in the proximity of the interface.