Abstract: The p-n junction is the foundation building structure for manufacturing various electronic and optoelectronic devices. Ultrawide bandgap semiconductors are expected to overcome the limited power capability of Si-based electronic device, however, it is very difficult to achieve efficient bipolar doping due to the asymmetric doping effect, thereby impeding the development of p-n homojunction and related bipolar devices, especially for the Ga₂O₃-based materials and devices. Here, we demonstrate a unique one-step integrated growth of p-type N-doped ($\bar{2}01$) β-Ga₂O₃/n-type Si-doped ($\bar{2}01$) β-Ga₂O₃ films by phase transition and in-situ pre-doping of dopants, and fabrication of full β-Ga₂O₃ linearly-graded p-n homojunction diode from them. The full β-Ga₂O₃ p-n homojunction diode possesses a large built-in potential of 4.52 eV, a high operation electric field > 2.90 MV/cm in the reverse-bias regime, good longtime-stable rectifying behaviors with a rectification ratio of 10⁴, and a high-speed switching and good surge robustness with a weak minority-carrier charge storage. Our work opens the way to the fabrication of Ga₂O₃-based p-n homojunction, lays the foundation for full β-Ga₂O₃-based bipolar devices, and paves the way for the novel fabrication of p-n homojunction for wide-bandgap oxides.

Key words: β-Ga₂O₃ films, in-situ pre-doping, Linearly-graded p-n junction, Forward and reverse characteristics, Built-in potential