A study of the structure of evaporated lithium fluoride

Abstract

The initial stages of growth of evaporated lithium fluoride films deposited on carbon have been studied. It has been shown that lithium fluoride deposits as discrete crystalline islands. The size of the islands is dependent on the rate of deposition; fast rates produce more and smaller islands than slow rates. As the film thickness increases, the islands are shown to reach a maximum area in the plane of the substrate, and then break up to give a greater number of smaller islands. Evidence is given to show that the initial nuclei of lithium fluoride are cubes of approximately 70 Å side. A theoretical growth model has been constructed on this basis and is shown to agree with experimental facts. There is considerable evidence that, in the initial stages of growth, the lithium fluoride islands are mobile on the substrates. Comparable measurements have been made on gold deposited on carbon substrates.