COEXISTENCE OF WURTZITE GAN WITH ZINC BLENDE AND ROCK-SALT STUDIED BYX-RAY POWER DIFFRACTION AND HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY

X-ray powder diffraction and high-resolution transmission electron mic roscopy (HRTEM) have found coexistence of three structures of GaN: wur tzite, zinc blende, and rocksalt in the samples prepared through benze ne thermal process at 280-300 degrees C under pressure about 5 MPa. Pr eviously, GaN with rocksalt structure only appeared at high pressure m ore than 37 GPa. HRTEM showed that there was a transitional region bet ween the two cubic phases of GaN with zinc blende and rocksalt. X-ray photoelectron spectra analysis of the sample gave the average composit ion of Ga0.95N. (C) 1996 American Institute of Physics.