Characterization of GaN synthesized in N-ion implanted GaAs

The hexagonal alpha-GaN phase (wurtzite) was synthesized in GaAs (001) by 7 0 keV N-2(+) ion implantation at 80 degrees C and subsequent furnace anneal ing at 850 degrees C for 10-30 min. N fluences used in this study were (2.0 -3.2)x10(17) cm(-2) X-ray diffraction analysis revealed that a buried layer of wurtzite-GaN was produced. Raman spectra were observed at around 525 cm (-1) together with LO- and TO-phonons from the GaAs matrix, suggesting the existence of a A(1)(TO) mode in GaN. X-ray photoelectron spectroscopy analy sis of the annealed samples also shows the peaks of Ga-2p3/2 (binding energ y: 1117.1 eV) and N-1s (397.5 eV). A broad photoluminescence spectrum rangi ng from 350 nm (3.5 eV) to 450 nm (2.76 eV) was observed in the annealed sa mples, indicating both the near band edge emission (3.45 eV for wurtzite ty pe GaN) and the impurity bands. (C) 1999 Elsevier Science B.V. All rights r eserved.