Defect formation in PbSe films during α-bombardment

The properties of lead chalcogenides are determined to a significant degree by the presence of intrinsic point defects. Depending on the synthesis conditions and subsequent thermal or radiation treatments of the material, both the type and the concentration of defects vary, considerably affecting its electrical parameters. However, accumulated experimental data and theoretical calculations show that defect formation in lead chalcogenides is complex and there is no unambiguous interpretation of the results obtained. Thus according to work on self-diffusion, it has been determined that the predominant type of defect in the cationic sublattice of PbSe is interstitial lead Pbi. Data on implantation of lead indicate that the interstitial metal atoms are singly ionized Pbi+. By hydrostatic weighing of PbSe it was determined that in p-type samples, doubly ionized lead vacancies VPb2- predominate. A number of authors have suggested the existence of vacancies in the chalcogen sublattice. Ideas in concerning the preferential formation of Frenkel defects in the metal sublattice satisfactorily explain some but certainly not all regularities in the synthesis of the material and its properties. Experimental results on ion implantation, bombardment by electrons, protons, and α-particles of AIVBVI crystals and films are confirmed by earlier models, suggesting formation of defects of both the donor and acceptor type in the form of stable open-quotes vacancy-interstitial atomclose quotes Frenkel pairs in the anionic and cationic sublattices simultaneously. The goal of this work was to clarify the nature of radiation defects in PbSe films upon bombardment by α-particles, based on comparison of experimental dose dependences of their electrical and structural parameters with the results of theoretical calculations