Characterization of rf-sputtered platinum films by positron annihilation spectroscopy

Abstract

Pt films on alumina substrates, both in their as-received and annealed states, have been extensively characterized by slow positron implantation spectroscopy ͑SPIS͒. Bulk Pt samples have been investigated by conventional positron annihilation spectroscopy ͑PAS͒ as well as by SPIS. A variety of state-of-the-art theoretical calculations have been performed to aid the interpretation of experimental findings. The research shows that a re-interpretation of earlier defect studies of bulk Pt by PAS is required in order to achieve a satisfactory agreement with the present experimental findings and theory.

Diffusion length of positrons and positronium investigated using a positron beam with longitudinal geometry

“…From the fitting procedure we obtain the positron diffusion lengths L + = 18± 1 nm for Al 2 O 3 and L + = 14± 1 nm for MgO. This value for Al 2 O 3 coincides with the result obtained by Brauer et al 17 for an ␣-Al 2 O 3 specimen after annealing for 1 hour at 800°C. Delocalized or Bloch Ps was never found in single crystal Al 2 O 3 and MgO and we can assume that the Ps is formed at the surface by electron capturing.…”

A study of positronium formation in anodic alumina

“…for polycrystalline γ -phase Al 2 O 3 . The last value is of the same order as that one obtained for single-crystalline Al 2 O 3 and α-Al 2 O 3 [5,19]. Due to the fact that L + is of the same order of magnitude as the channel wall thickness (see figure 1(b)) we can draw the conclusion that most of the Ps reach the channels.…”

Defect production in ion-implanted yttria-stabilized zirconia investigated by positron depth profiling

“…Nevertheless, when using the VEPFIT analysis [12], they provide convenient starting points to extract a positron diffusion length in the bulk: Λ + = 2.5 ± 0.5 nm. This length, at least four times lower than that found in annealed Al 2 O 3 [14] or in SiO 2 [15], suggests that Y-FSZ virgin samples indeed contain a significant amount of positron traps. These traps have been tentatively identified by Wang et al [16] as neutral complexes…”