Solid-phase epitaxy (SPE) of beta-Ga2O3 thin films by radio-frequency (RF) sputtering and then crystallized through high-temperature post-deposition annealing is employed on sapphire substrates, yielding a high-quality pseudo-substrate for subsequent buffer growth via MOCVD and LPCVD. Low roughness (<0.5 nm) and sharp single-crystalline diffraction peaks corresponding to the (-201), (-402), and (-603) reflections of beta-Ga2O3 were observed in the SPE beta-Ga2O3 film and the subsequent epitaxial buffer layer. N-doped Ga2O3 film on SPE Ga2O3 film grown by LPCVD showed step-assisted growth mode with reasonable electronic behavior with 45 cm^2/V-s mobility at a bulk carrier concentration of 1.3e17 cm^-3. These results suggest that SPE Ga2O3 is a promising pathway to advance the development of beta-Ga2O3 on foreign substrates.
@article{arxiv.2512.09294,
title = {Single-crystalline high-quality beta-Ga2O3 pseudo-substrate on sapphire through sputtering for epitaxial deposition},
author = {Guangying Wang and Shuwen Xie and William Brand and Saleh Ahmed Khan and Ahmed Ibreljic and Darryl Shima and Yueying Ma and Brahmani Challa and Fikadu Alema and Andrei Osinsky and Anhar Bhuiyan and Ganesh Balakrishnan and Shubhra S. Pasayat},
journal= {arXiv preprint arXiv:2512.09294},
year = {2025}
}