Molecular-beam-epitaxy growth of GaN on GaAs(100) by using reactive nitrogen source

By using a cold cathode ion gun to ionize the nitrogen gas, the molecular-beam-epitaxy growth of GaN is carried out. The zinc-blende structure GaN epilayer grown on the GaAs(100) substrate with a narrow x-ray diffraction peak width (FWHM) of 23 min and a low carrier concentration of 1017 cm−3 is achieved. The surface optical phonon energies of cubic and hexagonal GaN are experimentally determined to be 82 and 90 meV, respectively.