Microstructure of platinum films on YSZ prepared by pulsed laser deposition

Abstract

Platinum films with different microstructures have been prepared on different substrates by pulsed laser deposition (PLD) and subsequent annealing. We used (1 1 1) and (1 0 0) orientated as well as polycrystalline yttrium-stabilized zirconia (YSZ) and amorphous quartz glass as substrates. The platinum films on all substrates are (1 1 1) orientated, but the microstructures are different and depend strongly on the microstructure of the substrate. On (nearly) single crystalline YSZ (1 1 1) the platinum films are also (nearly) single crystalline. On YSZ (1 1 1) with defects these defects can also be found within the platinum films (mostly twins). The platinum films on (1 0 0) orientated and on polycrystalline YSZ as well as on quartz glass are polycrystalline. The angle between the grains on (1 0 0) YSZ is 30° or 60°. In addition, small angle grain boundaries can also be found. On quartz glass and polycrystalline YSZ the grain boundary angles are homogenously distributed in principle, but with a small preference for small angles and twin grain boundaries. The grain size depends on the substrate and varies between 300 nm and 10 μm. Eventually, the closer the texture of the substrate is to the (1 1 1) orientation, the larger is the ordering (larger grain size and higher sharpness of the texture) within the platinum films. Also, μm-sized droplets and holes can be found. The droplets are formed during PLD and their number is reduced during annealing. The holes are formed during annealing and emerge partly from droplets. In addition, located at the interface between the substrate and the platinum film there are voids of up to ca. 100 nm in size.