Atomic Environment of Positrons Annihilating in Different Parts of Cz-Si Single Crystal

intrinsic point defects. Abstract. The distribution of the positron-sensitive oxygen-induced as-grown point defects has been studied along the axis of growth of the single crystal Cz-Si and along the radial direction at the central part of the ingot. The one-dimensional angular correlation of the annihilation radiation (1D-ACAR) has been measured. The characteristic electron-positron ion radius and the “cut-off ” angle of 1D-ACAR [111] (to be characterised both by the ionic radii of atoms and the electron density in the lattice site where the annihilation of positron occurs) have been determined by the experimental findings. The probabilities of the correlated events of the high-momentum and low-momentum annihilation are redistributed when the microstructure of the oxygen complexes with intrinsic point defects is changed. The interpretation of the results is based on the conception of the positron localization in the field of negative effective charge resulted from relatively high electron affinity of oxygen. A role of involvement of the intrinsic point defects in the formation of the composition of the positron-sensitive centres is discussed.

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