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 = 2 pi/k(FSDP)) and (D = 2 pi/Delta k(FSDP)) characterizing the intermediate structures, and their volume fraction (nu proportional to Area(FSDP)) 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. (c) 2004 Elsevier B.V. All rights reserved.