Coexistence of wurtzite GaN with zinc blende and rocksalt studied by x-ray power diffraction and high-resolution transmission electron microscopy

X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM) have found coexistence of three structures of GaN: wurtzite, zinc blende, and rocksalt in the samples prepared through benzene thermal process at 280-300 degrees C under pressure about 5 MPa. Previously, GaN with rocksalt structure only appeared at high pressure more than 37 GPa. HRTEM showed that there was a transitional region between the two cubic phases of GaN with zinc blende and rocksalt. X-ray photoelectron spectra analysis of the sample gave the average composition of Ga0.95N. (C) 1996 American Institute of Physics.