Surface kinetics and viscosity in amorphous As₂₀Se₈₀: a comparative study of bulk and thin films prepared by thermal evaporation and spin-coating

A proper understanding of the molecular transport occurring in the near-surface region is a crucial prerequisite for the successful application of amorphous chalcogenides. This study provides information on the surface pattern decay in bulk samples and thin films of amorphous As₂₀Se₈₀. Single-period sinusoidal gratings were embossed into the sample surfaces, and subsequent annealing-induced decay or flattening of the surface grating was analyzed to obtain the rate constant of the process. The studies were performed in bulk samples, thermally evaporated thin films, and, for the first time, in solution processed chalcogenide thin films prepared by spin-coating. The obtained data provide a comparison of near-surface molecular transport in the As₂₀Se₈₀ amorphous material prepared by different methods.