Chemical lift-off of (11-22) semipolar GaN using periodic triangular cavities

► (11-22) semipolar GaN including periodic triangular cavities was grown by MOCVD. ► 300 μm thick (11-22) semipolar GaN was regrown to keep the exposed N-polar GaN. ► The N-polar GaN can be etched to (0002) direction with high etching rate. ► The thick (11-22) semipolar GaN was completely separated from the m-plane sapphire. ► The free-standing (11-22) semipolar GaN without m-sapphire was strain-free.