Abstract
Wurtzite ( metal) themselves are of interest as semiconductors with tunable band gap, insulating motifs to superconductors, and piezoelectric crystals. Characterization of wurtzite is challenging because of the difficulty to synthesize them as single-phase solid solution and such thermodynamic, elastic properties, and high temperature behavior of wurtzite is unknown. Here, we investigated the high temperature decomposition behavior of wurtzite films using experimental methods combined with first-principles calculations. We have developed a method to grow single-phase metastable wurtzite (, 0.75, 085, and 0.95) solid-solution films by cathodic arc deposition using low duty-cycle pulsed substrate-bias voltage. We report the full elasticity tensor for wurtzite as a function of Al content and predict a phase diagram including a miscibility gap and spinodals for both cubic and wurtzite . Complementary high-resolution scanning transmission electron microscopy and chemical mapping demonstrate decomposition of the films after high temperature annealing (), which resulted in nanoscale chemical compositional modulations containing Ti-rich and Al-rich regions with coherent or semicoherent interfaces. This spinodal decomposition of the wurtzite film causes age hardening of 1–2 GPa.
3 More- Received 31 May 2023
- Accepted 5 December 2023
DOI:https://doi.org/10.1103/PhysRevMaterials.8.013602
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by Bibsam.
Published by the American Physical Society