Raman scattering in As-Se-S and As-Se-Te Chalcogenide vitreous semiconductors

Chalcogenide vitreous semiconductors of As-Se-S and As-Se-Te compositions are synthesized, with thin films produced by thermal evaporation in vacuum. X-ray phase analysis and Raman spectroscopy are used to confirm their amorphous state and examine their structural specific features. It is shown that the matrices of both materials have a network-chain structure with covalent bonds between As, Se, S, and Te atoms. Structural units of the type of AsSe 3 and AsS 3 pyramids, AsSe 3/2 bipyramids, and α(β)-As 4 S 4 molecules exist in the As-Se-S matrix, and AsSe 3 , AsSe 3/2 , As 2 Se 3 , and As 2 Te 3 units, in As-Se-Te. The vibrational modes of Se-Se, Te-Te, As-As, As-S, Se-As-Se, As-Se-As, Se-As-S, Se-As-Te, and Se-Te bonds constituting both separate molecules and amorphous matrices are determined.