Growth of stoichiometric TiO₂ thin films on Au(100) substrates by molecular beam epitaxy

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• 作者：A. Calloni ; ^{alberto1.calloni@mail.polimi.it} ; A. Ferrari ; A. Brambilla ; F. Ciccacci ; L. Duò
• 关键词：Titanium oxide ; Gold ; Epitaxial growth ; Rutile (100) ; X-ray photoelectron spectroscopy ; Low-energy electron diffraction ; Ultraviolet photoemission spectroscopy ; Inverse photoemission spectroscopy
• 刊名：Thin Solid Films
• 出版年：2012
• 期刊代码：78_00406090
• 类别：ph
• 出版时间：30 March, 2012
• 卷：520
• 期：11
• 页码：3922-3926
• 文件大小：671 K

摘要

The present study reports on the growth of thin TiO₂ films onto Au(100) single crystals by Ti evaporation in a reactive O₂ atmosphere at two different substrate temperatures: room temperature (RT) and 300 掳C. The growth of the oxide films was monitored by means of X-ray photoemission spectroscopy, while the valence and conduction band electronic structure was investigated by UV and inverse photoemission spectroscopy, respectively.

The TiO₂ film grows epitaxially on the Au(100) substrate at 300 掳C exhibiting the rutile (100) surface. The evolution of the Ti 2p lineshape with the oxide coverage shows the presence of reduced oxide species (characterized by Ti^3 + ions) at the Au(100) interface. A crystalline and stoichiometric TiO₂ oxide is produced at high substrate temperature, while growth at RT gives a measurable concentration of defects. Post growth annealing in ultra-high vacuum of the RT grown film increases this concentration, while subsequent annealing in O₂ atmosphere restores the sample to the as-grown conditions.