LAUSR

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 [ 0001¯$000\bar{1}$ ] and [0001] directions in both GaN thin films and nanowires. Hexagonal pyramidal nanostructures consisting of six semipolar {11¯01}$\{ {1\bar{1}01} \}$ planes and one (000 1¯$\bar{1}$ ) 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.