Demonstration of n-Ga₂O₃/p-GaN Diodes by Wet-Etching Lift-Off and Transfer-Print Technique

In this letter, a 400-nm-thick $\beta $ -Ga ₂ O ₃ nanomembrane is extracted from an n-Ga ₂ O ₃ -on-silicon wafer by wet etching, and then transferred to a p-GaN/ sapphire wafer by transfer-print technique to fabricate n-Ga ₂ O ₃ /p-GaN heterojunction diodes. X-ray photoelectron spectroscopy (XPS) measurement is used to accurately confirm that the valence-band offset of the heterojunction is 1.41± 0.07 eV. The diodes exhibit excellent electrical properties including high rectification ratio ( ${3.85}\times {10} ^{{6}}$ at ±5 V) and low reversed current density ( ${1.51}\times {10} ^{-{7}}\,\,\text{A}\cdot $ cm ⁻² at −5 V). The results show that the lift-off and transfer-print processes pave a new way for fabricating high-performance Ga ₂ O ₃ -based heterojunctions and bipolar devices.