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Medientyp:
E-Artikel
Titel:
Optical properties of Si- and Mg-doped gallium nitride nanowires grown by plasma-assisted molecular beam epitaxy
Beteiligte:
Furtmayr, Florian;
Vielemeyer, Martin;
Stutzmann, Martin;
Laufer, Andreas;
Meyer, Bruno K.;
Eickhoff, Martin
Erschienen:
AIP Publishing, 2008
Erschienen in:
Journal of Applied Physics, 104 (2008) 7
Sprache:
Englisch
DOI:
10.1063/1.2980341
ISSN:
0021-8979;
1089-7550
Entstehung:
Anmerkungen:
Beschreibung:
The optical properties of GaN nanowires grown by catalyst free plasma-assisted molecular beam epitaxy on Si (111) are investigated by photoluminescence (PL) spectroscopy. The influence of the Si- and Mg-flux as well as the III-V ratio during growth on the PL properties is discussed. The Mg concentration as determined by secondary ion mass spectroscopy ranges from 5×1018 to 1×1020 cm−3. Raman scattering reveals that the nanowires are strain-free, irrespective of Si- or Mg-doping. The near band-edge emission of undoped or slightly Si-doped material is dominated by the narrow D0X recombination at 3.4715 eV with a full width at half maximum of 1.5 meV at 4 K. For high Si-fluxes, a blueshift of the D0X peak by 1 meV is found, which is attributed to band-filling effects. For moderate Mg-fluxes the acceptor-bound exciton recombination was detected at 3.4665 eV. Point defects due to the N-rich growth conditions are discussed as the origin of the emission band at 3.45 eV. Recombination at coalescence boundaries were identified as the origin of an emission band at 3.21 eV. The luminescence properties below 3.27 eV in highly Mg-doped samples are shown to be affected by the presence of cubic inclusions in the otherwise wurtzite nanowires.