Photophysics of Atomically Thin Freestanding β-Ga <sub>2</sub> O <sub>3</sub> Nanosheets: Implications for Luminescent Thermometry
Atomically thin non-van der Waals oxides are difficult to access because strong 3D bonding resists exfoliation. Here we report an amine-assisted liquid-phase exfoliation that produces freestanding β-Ga2O3 nanosheets only 2.1–2.4 nm thick with lateral sizes up to ∼10 μm, while preserving the monoclinic β-phase and a bulk-like bandgap of 4.79 ± 0.10 eV. Temperature-dependent luminescence reveals emergent 2D photophysics: self-trapped-hole emission dominates at low temperature, whereas a 2.4 eV green band exhibits negative thermal quenching from 80 to 200 K, consistent with self-trapped-hole migration to near-surface gallium-vacancy centers and highlighting opportunities for luminescent thermometry and optical sensing.
Authors
- Matthew R. Phillips (ORCID: https://orcid.org/0000-0003-1522-9281)
- Aviraj Ingle
- Amar K. Salih
- Cuong Ton‐That (ORCID: https://orcid.org/0000-0003-3276-1739)
- Vipul Bansal (ORCID: https://orcid.org/0000-0002-3354-4317)
- Sanje Mahasivam (ORCID: https://orcid.org/0000-0001-9975-3659)
- Bruce Cowie
- Curtis Irvine
Institutions
- University of Technology Sydney (AU)
- Australian Nuclear Science and Technology Organisation (AU)
- Australian Synchrotron (AU)
- MIT University (MK)
- NanoBio (United States) (US)
- RMIT University (AU)
Publication Details
- Journal
- ACS Applied Nano Materials
- Published
- 2026-05-27
- DOI
- https://doi.org/10.1021/acsanm.6c01440
- Primary Topic
- Ga2O3 and related materials
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Australian Nuclear Science and Technology Organisation
- Australian Research Council