Demonstration of mechanically exfoliated β -Ga₂O₃/GaN p-n heterojunction

This work demonstrates the construction of p-n heterojunctions between mechanically exfoliated beta-phase gallium oxide (β-Ga₂O₃) and p-GaN. The detailed mechanical exfoliation process was developed and can be used for further device applications. The atomic force microscopy study showed that the exfoliated β-Ga₂O₃ flakes had a very smooth surface with a roughness of 0.65 nm. Transmission electron microscopy revealed a clearly defined interface between the exfoliated β-Ga₂O₃ and p-GaN. The p-n heterojunction exhibited a turn-on voltage of 3.6 V and a rectification ratio of ∼10⁵. The heterojunction also showed good thermal performance up to 200 °C. Ideality factors and turn-on voltages decrease with temperature, tending toward the ideal threshold voltage of 3.2 V as determined by Silvaco simulations. This work provides valuable information on a mechanically exfoliated β-Ga₂O₃/GaN p-n heterojunction, which opens up the opportunities for a variety of photonic and electronic applications.