A NOVEL VAPOR-DEPOSITION EFFECT IN AMORPHOUS SUBSTANCES AS AN ARTIFACT

It was found, in the course of the electron-microscope study of fibrous objects of several kinds, that standard replicating and shadowing agents, such as carbon, platinum-carbon, and silicon monoxide, produce a structured overgrowth effect consisting of fine-scale side growths of about 100 Å width and a few hundred angstroms length giving the fiber a fir-tree-like appearance. The same effect is observed along edges of films. The direction of the growth is related both to the shadowing direction and to the orientation of the fiber or edge, and it may give a deceptive impression of this feature being a genuine characteristic of the sample investigated. Misinterpretation of electron micrographs due to this source has already come to our attention. The effect is of interest also from the point of view of vapor deposition in general. It is likely to be a manifestation of structured deposition occurring on all levels including the macroscopic. While the effect remains unexplained, some of the relevant features are presented in this paper. © 1968 The American Institute of Physics.