Positron annihilation in boron nitride crystals

The dislocation structure of the zincblende form of BN is investigated. The crystals of 3 to 5 μm in diameter are compressed under 60 kbar at temperatures of 20, 500, and 1500 °C and the angular correlation spectra of annihilation photons are measured. The results are interpreted as follows: The positrons are trapped at the Bdislocations and the fraction of dangling bonds αd ≈ 0.6 corresponds to that of GaAs for Gadislocations. [Russian text Ignored.]