Comparison of atomic structures and electronic properties of amorphous AsSe films

The atomic structure and electrical and optical properties of amorphous AsSe films prepared by thermal evaporation in a vacuum and by rf ion-plasma sputtering have been studied. The conductivity, activation energy of conductivity, optical gap, radii of the first and second coordination spheres, number of the nearest neighbours of arsenic and selenium atoms in the first coordination sphere and dimensions of the medium-range order domain in the atomic structure have been determined for the samples studied. Films prepared by different methods have dissimilar electrical and optical parameters and show differences in atomic structure, mainly related to the dimensions of the medium-range order domains. A conclusion is made that it is the medium-range order in the amorphous film atomic structure in the As-Se system that governs the electronic structure of amorphous films of the As-Se system.