The influence of γ‐irradiation on the positron annihilation lifetime spectra in chalcogenide vitreous semiconductors of As‐Ge‐S system has been analysed. The correlations between lifetime data, structural features and chemical compositions of glasses have been discussed. The observed lifetime components are connected with bulk positron annihilation and positron annihilation on various native and γ‐induced open volume defects. It is concluded that after γ‐irradiation of investigated materials the γ‐induced microvoids based on S1–, As2–, and Ge3– coordination defects play the major role in positron annihilation processes.

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A principally new cation‐interlinking network cluster approach (CINCA) was proposed to describe different types of glass‐forming structural units in network covalent‐bonded solids like to chalcogenide vitreous semiconductors. Within this approach, two (or three) interconnected cation‐centered polyhedra form more stretched structural fragments conditionally named atomic clusters, reflecting in such a way whole backbone of covalent‐bonded semiconductor multiply duplicated in a space. The probability of possible atomic clusters is estimated with numerical parameter giving average formation energy in respect to the number of atoms involved in the cluster and average coordination number. This approach was probed at the example of regular network clusters based on AsS3/2 pyramids mutually‐interconnected through bridge ‐S‐ atom contrasted with irregular double‐bond‐based quasi‐tetrahedral structural S = AsS3 defects within binary As‐S system. The corresponding mathematical calculations confirming a preference of regularly‐linked structural units over irregular ones was performed using HyperChem 7.5 program. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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