Study of the growth and structure of antimony films on carbon substrates in low and high vacuum

Abstract

The growth of antimony thin films in low (1 × 10−5 Torr) and high (5 × 10−8 Torr) vacuum has been studied by transmission electron microscopy. The films have been evaporated on amorphous carbon substrates at room temperature. Initially the films took the form of islands which coalesced as they grew in size. Measurements of island density, size and inter-island spacing was made for films of different thicknesses and their variation with film thickness was plotted. The distribution of particle size in a film with an average thickness of 25 Å was measured. These quantities were identical for both vacua. The electrical continuity of a film evaporated on glass has been observed for a film about 120 Å thick. The drop in electrical resistivity is abrupt at that thickness. Electron diffraction patterns have been obtained for selected areas of films of various thickness. It was observed that before continuity was reached all films at both pressures were amorphous in nature. After continuity was reached, the films deposited in high vacuum become crystalline, whereas those deposited in low vacuum retained their amorphous nature.