Short-range order in amorphous GeTe films

Abstract

Thin films of amorphous (stoichiometric) GeTe have been examined by direct recording of electron diffraction, and intensity profiles across the diffuse diffraction pattern have been recorded with electrostatic rejection of inelastically scattered electrons. Radial distribution analysis of these curves shows that the local order is not characteristic of the distorted rocksalt structure of bulk GeTe, i.e., nearest-neighbor distance of 2.99 Å and nearest-neighbor coordination of 6. Instead it is found that the nearest-neighbor distance is 2.65 Å with coordination of approximately 4. This result is of significance for the interpretation of the electronic properties of amorphous films.