Tuning Thermal Transport in Radio-Frequency-Sputtered Beta-Gallium Oxide Through Thickness and Plasma-Induced Interface Modification
5 affiliations
- 1Center for Energy and Advanced Materials Science, National Laboratory Astana, Astana 010000, Kazakhstan
- 2Department of Physics, School of Sciences and Humanities, Nazarbayev University, Astana 010000, Kazakhstan
- 3Institute of New Materials and Energy Technologies, 53 Kabanbay Batyr Ave., 010000 Astana, Kazakhstan
- 4Department of Physical Electronics, Faculty of Physics and Technology, Dagestan State University, Makhachkala 367000, Russia
- 5Centre for HRTEM, Nelson Mandela University, Port Elizabeth 6001, South Africa
Abstract
Controlling heat flow in beta-gallium oxide (β-Ga2O3) thin films requires understanding both phonon transport within the semiconductor and heat transfer across metal/semiconductor interfaces. Here, we investigate these pathways in high-temperature radio-frequency magnetron-sputtered β-Ga2O3 films grown on c-plane sapphire with thicknesses from 0.42 to 2.1 μm. The thermal conductivity increases from 5.4–6.9 W m−1 K−1 in the 420 nm film to approximately 10–12 W m−1 K−1 in the thicker films. Structural characterization reveals thickness-dependent microstructural evolution, including grain coarsening and intergranular void-like defects. An analytical Debye–Klemens model incorporating phonon scattering from film boundary and defects reproduces the overall thickness dependence. The Ar plasma-treated samples exhibit Al/β-Ga2O3 thermal boundary conductance values of approximately 100 MW m−2 K−1, about 70% higher than the untreated sample (~60 MW m−2 K−1), while the thermal conductivity of the underlying films remains within a comparable range. Picosecond acoustic measurements, transmission electron microscopy and electron energy loss spectroscopy reveal a corresponding modification of the interfacial acoustic response and formation of an ultrathin amorphous/disordered near-surface region. Although variations between independent deposition runs cannot be excluded, these findings suggest that thickness-dependent microstructure and plasma-associated interface modifications offer promising approaches to tailoring thermal transport in β-Ga2O3-based devices.
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BibTeX
@article{abdullaev2026tuning,
title = {{Tuning Thermal Transport in Radio-Frequency-Sputtered Beta-Gallium Oxide Through Thickness and Plasma-Induced Interface Modification}},
author = {Azat Abdullaev and Rustem Tlegenov and Magomed A. Umakhanov and Jacques O’Connell and Abubakar M. Ismailov and Kairolla Sekerbayev and Zhandos N. Utegulov},
journal = {Nanomaterials},
year = {2026},
month = nov,
doi = {10.3390/nano16211439},
url = {https://www.mdpi.com/2079-4991/16/21/1439},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Tuning Thermal Transport in Radio-Frequency-Sputtered Beta-Gallium Oxide Through Thickness and Plasma-Induced Interface Modification
AU - Azat Abdullaev
AU - Rustem Tlegenov
AU - Magomed A. Umakhanov
AU - Jacques O’Connell
AU - Abubakar M. Ismailov
AU - Kairolla Sekerbayev
AU - Zhandos N. Utegulov
PY - 2026
DA - 2026/11/06
JO - Nanomaterials
DO - 10.3390/nano16211439
UR - https://www.mdpi.com/2079-4991/16/21/1439
AB - Controlling heat flow in beta-gallium oxide (β-Ga2O3) thin films requires understanding both phonon transport within the semiconductor and heat transfer across metal/semiconductor interfaces. Here, we investigate these pathways in high-temperature radio-frequency magnetron-sputtered β-Ga2O3 films grown on c-plane sapphire with thicknesses from 0.42 to 2.1 μm. The thermal conductivity increases from 5.4–6.9 W m−1 K−1 in the 420 nm film to approximately 10–12 W m−1 K−1 in the thicker films. Structural characterization reveals thickness-dependent microstructural evolution, including grain coarsening and intergranular void-like defects. An analytical Debye–Klemens model incorporating phonon scattering from film boundary and defects reproduces the overall thickness dependence. The Ar plasma-treated samples exhibit Al/β-Ga2O3 thermal boundary conductance values of approximately 100 MW m−2 K−1, about 70% higher than the untreated sample (~60 MW m−2 K−1), while the thermal conductivity of the underlying films remains within a comparable range. Picosecond acoustic measurements, transmission electron microscopy and electron energy loss spectroscopy reveal a corresponding modification of the interfacial acoustic response and formation of an ultrathin amorphous/disordered near-surface region. Although variations between independent deposition runs cannot be excluded, these findings suggest that thickness-dependent microstructure and plasma-associated interface modifications offer promising approaches to tailoring thermal transport in β-Ga2O3-based devices.
SN - 2079-4991
ER -