Characterization of evaporated erbium films at various stages of growth

In this paper, the phases and structure of evaporated erbium films at various stages of growth and the influence of deposition conditions including deposition rate, residual gases, substrate temperature, and substrate material on these films are investigated. In accordance with the findings of other workers, our experiments show that under typlcal UHV conditions and at ambient temperature the thinner erbium films are erbium dihydride with f.c.c. structure rather than erbium metal. However, if residual hydrogen and water vapour are reduced, ultra-thin pure erbium films with h.c.p. structure can be prepared. For films deposited onto high temperature substrates (356°C), the films are strongly influenced by substrate material; thicker films deposited on glass substrates contain mainly h.c.p. erbium metal, whereas the thicker films deposited on carbon substrates show amorphous nature. Erbium oxide is found in the thinner films deposited at high temperature on both glass and carbon substrates. At both ambient and high substrate temperatures, the 〈001〉 preferred o rientation of erbium metal crystallites with h.c.p. structure is found even at their earliest stages of growth.