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Local Electron Beam Induced Reduction and Crystallization in Electrochemically Deposited Amorphous TiO2 Films

Published online by Cambridge University Press:  01 February 2011

Philippe Kern  and
Johann Michler
Philippe Kern
Affiliation:
philippe.kern@empa.ch, Empa, Materials Science Technology, Feuerwerkerstrasse 39, Thun, 3602, Switzerland, +41 33 228 36 26, +41 33 228 39 46
Johann Michler
Affiliation:
johann.michler@empa.ch, Empa, Materials Science Technology, Feuerwerkerstrasse 39, Thun, 3602, Switzerland
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Abstract

Contrary to crystalline titanium oxide (TiO2), electrochemically deposited amorphous thin TiO2 films are found significantly more sensitive towards electron beam (e-beam) exposure. E-beam irradiation experiments were performed under scanning electron microscope conditions at 20 keV with well controlled beam current (IP), current density and exposure dose. As shown by atomic force microscopy and Micro-Raman spectroscopy, even moderate e-beam exposure immediately leads to oxide reduction due to electron stimulated oxygen desorption, while exposure with IP>1 micro-A and J>1 A/cm2 triggers localized crystallization into anatase phase already after seconds of irradiation. The mechanisms for oxide reduction and beam heating induced crystallization are discussed, and a temperature estimation in the beam center indicates that crystallization occurs at less than 150 °C. The well-defined volume loss upon oxygen desorption is shown to be attractive for precise topographical surface patterning, while the triggering local structural changes within a semi-conductive amorphous matrix opens interesting possibilities for tailoring of its local electrical or catalytic properties.

Keywords

oxideelectron irradiationamorphous
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 950: Symposium D – Biosurfaces and Biointerfaces , 2006 , 0950-D15-18
Copyright
Copyright © Materials Research Society 2007

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