Growth modes in metal-organic molecular beam epitaxy of TiO2 on r -plane sapphire

Bharat Jalan, Roman Engel-Herbert, Jol Cagnon, Susanne Stemmer

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33 Scopus citations


Phase pure, epitaxial (101) rutile TiO2 films were grown on (012) sapphire substrates at temperatures between 485 and 725 °C using metal-organic molecular beam epitaxy with titanium tetraisopropoxide as the Ti source. Growth modes and rates were investigated as a function of substrate temperature using reflection high-energy electron diffraction, x-ray reflectivity, atomic force microscopy, and transmission electron microscopy. Growth rates were as high as 125 nm/h. The influence of additional oxygen supplied from a rf plasma source was investigated. Without oxygen plasma, the growth rate exhibited reaction and flux-limited regimes and layer-by-layer growth was observed in the initial stages of film growth. With oxygen plasma the growth rate became independent of temperature; films grew initially in step-flow mode and were insulating. The mechanisms for the different growth modes as a function of film thickness, temperature, and presence of oxygen are discussed.

Original languageEnglish (US)
Pages (from-to)230-233
Number of pages4
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Issue number2
StatePublished - 2009

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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