Alternative low-pressure surface chemistry of titanium tetraisopropoxide on oxidized molybdenum

Alexis M. Johnson, Peter C. Stair*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Titanium tetraisopropoxide (TTIP) is a precursor utilized in atomic layer depositions (ALDs) for the growth of TiO2. The chemistry of TTIP deposition onto a slightly oxidized molybdenum substrate was explored under ultrahigh vacuum (UHV) conditions with X-ray photoelectron spectroscopy. Comparison of the Ti(2p) and C(1s) peak areas has been used to determine the surface chemistry for increasing substrate temperatures. TTIP at a gas-phase temperature of 373 K reacts with a MoOx substrate at 373 K but not when the substrate is at 295 K, consistent with a reaction that proceeds via a Langmuir-Hinshelwood mechanism. Chemical vapor deposition was observed for depositions at 473 K, below the thermal decomposition temperature of TTIP and within the ALD temperature window, suggesting an alternative reaction pathway competitive to ALD. We propose that under conditions of low pressure and moderate substrate temperatures dehydration of the reacted precursor by nascent TiO2 becomes the dominant reaction pathway and leads to the CVD growth of TiO2 rather than a self-limiting ALD reaction. These results highlight the complexity of the chemistry of ALD precursors and demonstrate that changing the pressure can drastically alter the surface chemistry.

Original languageEnglish (US)
Pages (from-to)29361-29369
Number of pages9
JournalJournal of Physical Chemistry C
Issue number50
StatePublished - Dec 18 2014

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Energy
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


Dive into the research topics of 'Alternative low-pressure surface chemistry of titanium tetraisopropoxide on oxidized molybdenum'. Together they form a unique fingerprint.

Cite this