Title: Polarity compensation on KTaO3(001) surfaces
Other Titles: Polaritätskompensationen der KTaO3(001) Oberfläche
Language: English
Authors: Pölzleitner, Flora Josefa 
Qualification level: Diploma
Advisor: Diebold, Ulrike 
Assisting Advisor: Setvin, Martin 
Issue Date: 2017
Number of Pages: 49
Qualification level: Diploma
This master thesis is focused on the structure of the KTaO3 (001) surface. Along this direction the cleaved surface is polar and several polarity compensation mechanisms are found depending on the applied conditions. In vacuum the as-cleaved surface consists of a mixture of bulk terminated KO and TaO2 terminated regions. At room temperature defect formation is observed and annealing results in rearrangement of the terraces, while the (1×1) termination is retained. The rearranged surface shows a labyrinthine structure with lines of 4-5 atoms width. This reconstruction is stable for annealing temperatures of up to 723 K. Exposure to water results in a hydroxylated surface and the formation of an overlayer with a (2×1) periodicity. The hydroxylated surface is stable for annealing temperatures of ~373 K and starts to decompose at annealing temperatures of ~473 K. Cleaved KTaO3 single crystals, which are doped by Ba, Yb and Cu, were investigated by atomic force microscopy (AFM), scanning tunneling microscopy (STM), low energy ion spectroscopy (LEIS), X-ray photoelectron spectroscopy (XPS) and low energy electron diffraction (LEED) under ultrahigh vacuum conditions. Experimental details with regard to the sample preparation and the influence of the applied surface science techniques are given. Structural models are proposed based on these experimental results and the stability of these structures is discussed.
Keywords: Oberflächenphysik; Rastersondenmikroskopie; Polare Oxidoberflächen
Surface physics; Scanning Probe Microscopy; polar oxide surfaces
URI: https://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-105623
Library ID: AC14507184
Organisation: E134 - Institut für Angewandte Physik 
Publication Type: Thesis
Appears in Collections:Thesis

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