Defect Characterization in Cu2NiX (X = SSe, Te2, SeTe) Chalcogenide Semiconductors Using Positron Annihilation Spectroscopy. - Samadov, S. F.; Guliyeva, Kh. M.; Sidorin, A. A.; Trung, N. V. M.; Aliyev, Y. I.; Orlov, O. S.; Jabarov, S. H. (Arabian Journal for Science & Engineering (Springer Science & Business Media B.V. ), 2026)