The analysis of chemical bonding and electronic environments in CVD grown gallium nitride nanowires

Gallium Nitride Nanowires (GaN-NWs) were synthesized on Si (100) substrates using chemical vapour deposition by ammoniating the Ga₂O₃ films with various H₂ flow rate. The as deposited GaN-NWs were characterized by AFM, XRD, Raman, PL and XPS techniques. The AFM images reveal the diameter of GaN-NWs is 40-80 nm. The XRD investigation confirms the wurtzite structure of GaN-NWs. The Raman results reveals several vibrational peaks at 465, 500, 569, 609, 622, 720 cm–1 corresponds to zone boundary phonon, acoustic overtone, E2(high), SO (A), SO (E) and A1(LO) respectively. The A1(LO) phonon shifted to higher wavenumber region indicates optical phonon confinement in the GaN-NWs with increasing of H2 flow rate. The broad PL spectra of GaN-NWs were observed at 2.82 and 2.96 eV indicates Nitrogen vacancy in GaN-NWs. The XPS results reveals the N(1s) binding energy shifted from 396.54 to 397.27 eV with increasing of H2 dilution from 40 to 120 sccm. (author)