On PbTiO{sub 3}-(111)-Pt interfacial layers and their x-ray photoelectron spectroscopy signature
- Institute for Materials and Surface Technology, University of Applied Sciences, D-24149 Kiel (Germany)
- Engineering Faculty, Materials Sciences Department, Christian-Albrechts University, D-24149 Kiel (Germany)
In this work emphasis is placed on the investigation of interfacial layers between sol-gel processed PbTiO{sub 3} (PTO) thin films and (111)Pt terminated silicon substrates. The methods used are x-ray diffraction, x-ray photoelectron spectroscopy (XPS) combined with depth profiling, and atomic force microscopy (AFM). In order to avoid artifacts related to ion bombardment, e.g., reduction of Pb ions and preferential sputtering, gentle argon ion bombardment conditions were first derived. AFM investigations of native and ion bombarded films at different stages of depth profiling show that the films are homogenously sputtered, whereby the film roughness remains practically unchanged in the course of sputtering. An annealing treatment at 550 deg. C under reducing atmosphere was used to provoke the formation of an interfacial intermetallic (111)Pt{sub x}Pb phase, which is shown to coexist with an amorphous oxide film. This could allow us to establish the XPS signature of the intermetallic phase. A negative shift of the Pt (4f) binding energy and a large full width at half maximum of the Pb (4f) peak are the attributes of this signature. PTO-film annealing in air at temperatures between 350 and 600 deg. C leads to the formation of the perovskite phase, starting at 500 deg. C, directly from the amorphous phase. Based on its derived XPS signature it is shown that the intermetallic phase still exists at the interface with variable thickness depending on the annealing temperature. The pronounced (111) texture of the PTO-crystallized films is thought to be the direct consequence of this intermetallic template layer. It is also shown that the outermost surface of the PTO film is enriched with PbO as a result of segregation phenomena.
- OSTI ID:
- 21185928
- Journal Information:
- Journal of Applied Physics, Vol. 104, Issue 10; Other Information: DOI: 10.1063/1.3014030; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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