Nano/meso-scale separation in some Ge-As-S glasses and amorphous films

Abstract

Atomic force microscopy (AFM) and atomic force acoustic microscopy (AFAM) is used for examination of the role of annealing and illumination of flexible network of Ge0.12As0.17S0.71 amorphous film and rigid network of Ge0.25As0.30S0.45 amorphous film. The virgin state of both films appears to be smooth with the value of smoothness Sa at around 0.8 nm. Annealing leads to changes in topological smoothness (Sa increased up to 5nm in case of S-rich film) attributed to a nano/meso phase separation associated, most probably, with sulfur aggregation in the case of Ge0.12As0.17S0.71 and arsenic aggregation in the case of Ge0.25As0.30S0.45 amorphous film. Illumination of virgin Ge0.12As0.17S0.71 amorphous film leads to less pronounced but similar results as obtained by annealing, while rigid Ge0.25As0.30S0.45 amorphous film is insensitive to used illumination.