Synchrotron Radiation X-Ray Diffraction Study of AlN Nanowires under High Pressures

The high-pressure behavior of wurtzite AlN nanowires is studied up to 51.1 GPa by in situ angle dispersive X-ray diffraction using synchrotron radiation source and a diamond anvil cell. With increasing pressure up to 24.9 GPa, the wurtzite-to-rocksalt phase transition was observed. The rocksalt phase is quenched after a complete pressure release. The axial ratio c/a of the wurtzite AlN nanowires decreases linearly with increasing pressure. The unique wire-like structure in AlN nanowires results in the high pressure behavior being different from that of the bulk and nanocrystal AlN.