Correlation between medium-range order in atomic structure and optical properties of amorphous AsSe films

Changes in the atomic structure and optical properties of amorphous films in the As-Se system upon annealing have been studied on films prepared by thermal evaporation in a vacuum and by RF ion-plasma sputtering. The annealing modifies the atomic structure of the films and shifts their optical absorption edge. Changes in the atomic structure mainly occur in the medium-range order. The most essential changes in the atomic structure and optical properties are observed for AsSe films. A correlation between changes in the medium-range order of the atomic structure and the optical gap of the films is established.