Atomic‐Scale Investigation of the Lattice‐Asymmetry‐Driven Anisotropic Sublimation in GaN

Thermal sublimation, a specific method to fabricate semiconductor nanowires, is an effective way to understand growth behavior as well. Utilizing a high‐resolution transmission electron microscope (TEM) with in situ heating capability, the lattice‐asymmetry‐driven anisotropic sublimation behavior is demonstrated of wurtzite GaN: sublimation preferentially occurs along the [[Formula: see text]] and [0001] directions in both GaN thin films and nanowires. Hexagonal pyramidal nanostructures consisting of six semipolar [Formula: see text] planes and one (000 [Formula: see text]) plane with the apex pointing to the [0001] direction are generated as a sublimation‐induced equilibrium crystal structure, which is consistent with the lattice‐asymmetry‐driven growth behaviors in wurtzite GaN. These findings offer a new insight into the thermal stability of wurtzite GaN and provide essential background for tailoring the structure of III‐nitrides for atomic‐scale manufacturing.