Epitaxial Growth of p-Type β-Ga2O3 Thin Films and Demonstration of a p–n Diode

Abstract

β-Ga₂O₃, with its ultrawide bandgap (∼4.9 eV) and well-established n-type conductivity, is a promising semiconductor for next-generation power electronics. However, the realization of stable p-type doping remains a fundamental challenge owing to the deep-acceptor levels of conventional dopants. Here, a Te–Mg co-doping strategy is developed via metal–organic chemical vapor deposition (MOCVD) to overcome this limitation. The co-doped films exhibit a room-temperature resistivity of 32.4 Ω·cm, a Hall hole concentration of 1.78 × 10¹⁷ cm⁻³, and mobilities up to 5.29 cm² V⁻¹ s⁻¹ at lower carrier concentrations (5.72 × 10¹⁴ cm⁻³). A preliminary p–n diode is successfully demonstrated. Density functional theory (DFT) calculations reveal that Te incorporation introduces an intermediate band near the valence band maximum (VBM), effectively reducing the Mg acceptor ionization energy. Spectroscopic analyses further confirm VBM elevation through Te–Ga orbital hybridization and a Fermi-level shift toward the valence band, consistent with p-type behavior. These results establish a viable route for achieving p-type β-Ga₂O₃ homoepitaxy and lay the groundwork for future optimization toward sub-1 Ω·cm resistivity and a deeper understanding of the Te–Mg doping mechanism, paving the way for bipolar device applications in ultrawide-bandgap electronics.