The radionuclide 77Br(77Se) was applied as a probe nucleus for the pertubed angular correaltion technique (PAC) to study the incorporation of group VII elements in the III-V compound semiconductors GaAs, InAs and InP and their interaction with defects. The properties of 77Br(77Se) regarding the PAC technique and different means of production of the probe nucleus are discussed.
In semiinsulating GaAs after annealing at 1123 K a uniform quadrupole interaction freuqenzy νQ=229(2) MHz with an axially symmetric field gradient (principal component Vzz oriented along ⟨111⟩) was observed at the site of all probes.
Similar to the situation in GaAs, in InP after annealing at 1023 K a high fraction of the probes is subjected to a uniform quadrupole interaction (νQ=170(2) MHz, η=0). In InAs however, all probes are found in a cubic environment after annealing at 923 K. Possible structural models for the observed defect complexes will be discussed.