Mesoscopic organization and structural phases in network-forming GexSe1-x glasses

We report X-ray diffraction study on 14 close-by compositions of the chalcogenide glass series, GexSe1-x (0.15=<x=<0.33). From the first sharp diffraction peak (FSDP) in the total structure factor S(k), length scales (d=2π/kFSDP) and (D=2π/ΔkFSDP) characterizing the intermediate structures, and their volume fraction (υ∝AreaFSDP) have been deduced, that refer to an enhanced level of structural organization beyond the nearest neighbors. Spectral-evolution of FSDP across the series is related to a complex-growth of mesoscopic organization, revealing three well-resolved structural phases that compositionally segregate the system