Fabrication and micro-photoluminescence investigation of Mg-doped gallium nitride nanorods

Abstract

High-density magnesium (Mg)-doped gallium nitride (GaN) nanorods were fabricated by inductively coupled plasma reactive ion etching from a GaN film and had a mean length of approximately 50nm. A large blue-shift was observed in the photoluminescence (PL) peak energy of Mg-doped GaN nanorods under HeCd laser (325 nm) excitation. The PL spectra of the nanorods show a typical donor-acceptor-pair (DAP) emission at approximately 3.0 eV with a large blue-shift compared to that of the Mg-doped GaN film. The blue-shift energy increases from 8 meV to 67 meV as the excitation intensity varies from 12 kW/cm(2) to 56 kW/cm(2). Possible reasons for the power dependence of the spectral shift in the PL emission energy are discussed.