  Organisms in nature can alter the short-range order of an amorphous precursor
phase, thereby controlling the resulting crystalline structure. This phenomenon
inspired an investigation of the effect of modifying the short-range order
within the amorphous phase of a selected material. Amorphous thin films of
aluminum oxide deposited by the atomic layer deposition method were found to
vary structurally as a function of size. Thinner films, as predicted and also
confirmed by atomistic simulations, exhibited more 4 coordinated alumina sites.
These atomistic alterations were expected to change the amorphous thin film
average density. The density indeed varied with the alumina layer thickness,
and the measured effect was even stronger than predicted theoretically. This
effect is explained in terms of the deposition process, where each newly
deposited layer is a new surface layer that remembers its structure, resulting
in thin films of substantially lower density.
