Phase Formation of Manganese Oxide Thin Films by Pulsed Laser Deposition

Lauren Garten, Praneetha Selvarasu, John Perkins, David Ginley, Andriy Zakutayev

Research output: Contribution to journalArticlepeer-review

Abstract

Manganese oxides have enabled a wide range of technologies including oxygen evolution catalysts, lithium ion batteries, and thermochemical water splitting. However, the variable oxidation state and rich polymorphism in manganese oxides make it difficult to find the processing conditions to target a particular phase of manganese oxide. Targeted synthesis requires a more complete understanding of the phase space and the impact of multiple processing variables on phase formation. Here we demonstrate the impact of substrate temperature, total deposition pressure, partial pressure of oxygen, and target composition on the phase formation of manganese oxides grown by combinatorial pulsed laser deposition (PLD). Thin films were deposited from either a MnO, Mn2O3 and MnO2 target onto amorphous glass substrates with a continuously varied temperature provided by a combinatorial heater. A combination of x-ray diffraction and Raman and Fourier transform infrared (FTIR) spectroscopy was used to determine the phases present in the samples. The oxygen partial pressure is found to be the most critical factor determining phase formation, while the total pressure, target composition, and substrate temperature have smaller but more complex effects on phase formation. Comparing the results of this work to published temperature - pressure phase diagrams shows that the PLD thin films vary significantly from the expected equilibrium phases for either bulk materials or nanoparticles. These results suggest that PLD provides a route to capture phases of manganese oxides at lower temperatures or higher oxygen pressures than required for bulk synthesis or solution processing.
Original languageAmerican English
Pages (from-to)303-309
Number of pages7
JournalMaterials Advances
Volume2
Issue number1
DOIs
StatePublished - 2021

NREL Publication Number

  • NREL/JA-5K00-77440

Keywords

  • manganese oxide
  • metastable materials
  • non-equilibrium synthesis
  • phase diagram
  • pulsed laser deposition

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