An Electron Microscope Investigation of the Structure of Some Amorphous Materials

Abstract

The structure of as deposited thin films of SiO2 and as deposited, as well as heated Si, Ge, and several Ge–Te alloys, has been investigated by transmission electron microscopy and electron diffraction. Using high resolution dark field microscopy it is shown that the structure of all the amorphous specimens investigated comprised of coherently scattering regions 10 to 20 Å in size. The coherently scattering regions are retained until crystallization in the Si, Ge, and GeTe films. In the case of tellurium‐rich Ge–Te alloys, the coherently scattering regions are found to disappear and reappear with temperature cycling. On the basis of the experimental evidence, it is suggested that the conventional microcrystalline model is not a valid description of amorphous materials. Copyright © 1972 WILEY‐VCH Verlag GmbH & Co. KGaA