Abstract
The photocatalyst β-TaON is of interest due to promising properties, such as stability, suitable band gap for visible light, and carrier mobility. We implemented a combinatorial, material discovery approach that used pulsed laser deposition (PLD) for thin-film growth, X-ray diffraction (XRD) for phase determination, and machine learning for data reduction. A lateral compositional gradient of TaOxNy was grown across the surface of an α-Al2O3 (012) wafer. After annealing, XRD scattering patterns were collected across the lateral gradient. Unsupervised machine learning separated the XRD data into four clusters (phases); one of which turned out to be the desired monoclinic β-TaON phase. Using high-resolution XRD, we determined that the β-TaON region of the film was a 260 Å thick single-crystal epitaxial with the substrate, having out-of-plane β-TaON (100)//α-Al2O3 (012) and in-plane β-TaON (010)//α-Al2O3 (210). X-ray reflectivity (XRR) analysis of the β-TaON region of the film showed an electron density matching that expected for β-TaON. X-ray photoelectron spectroscopy (XPS) showed a Ta5+ valence state in the β-TaON region of the film. This combinatorial approach, which produces a library of phases on a single wafer, proved to be very efficient for the growth of a material’s phase of interest.
Original language | English (US) |
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Pages (from-to) | 3571-3576 |
Number of pages | 6 |
Journal | ACS Applied Electronic Materials |
Volume | 2 |
Issue number | 11 |
DOIs | |
State | Published - Nov 24 2020 |
Funding
This research was primarily supported by the US National Science Foundation (NSF) MRSEC Program (DMR-1720139) at Northwestern University (NU). This work made use of the X-Ray Diffraction, Pulsed Laser Deposition, and Keck-II facilities at NU supported by the MRSEC program of the (NSF DMR-1720139), Keck Foundation, State of Illinois, and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205).
Keywords
- Combinatorial synthesis
- Machine learning
- PLD
- Thin film
- XRD
- β-TaON
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Electrochemistry