Low-temperature growth of epitaxial Li3xLa(2/3−x)TiO3 thin films by RF magnetron sputtering
Year: 2026
Type: article
Abstract: Epitaxial thin films of the lithium ionic conductor Li 3x La (2/3-x) TiO 3 were successfully grown on Al 2 O 3 (0001) substrates by RF magnetron sputtering using a ceramic target containing 10 mol% excess Li. The effects of deposition temperature, Ar:O 2 gas-flow ratio, and working pressure on film growth were systematically investigated. XRD revealed highly (112)-oriented tetragonal LLTO, with no consistent set of reflections attributable to secondary crystalline phases. Substrate-referenced azimuthal φ-scans of the representative film deposited at 650 °C confirmed a well-defined in-plane orientation relationship between LLTO and the Al 2 O 3 (0001) substrate, with two symmetry-related rotational variants. The Ar:O 2 ratio strongly affected the out-of-plane coherent domain size. SEM revealed changes in surface morphology with deposition temperature, while AFM showed a clear influence of the Ar:O 2 gas-flow ratio on surface topography. XPS confirmed Li at the surface, with La and Ti predominantly present as La 3+ and Ti 4+ , respectively, together with a temperature-dependent variation in surface hydroxylation. Overall, based on the combined structural results and available morphological observations, 650 °C, Ar:O 2 = 7:1 (i.e., oxygen-poor mixture), and 0.1 Torr were selected as favorable conditions within the investigated parameter range, supporting further development of LLTO thin films for all-solid-state pH-sensing applications.
Source: Surface and Coatings Technology
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,880
Funder: Université Paris-Saclay
OpenAlex ID: W7224198437