Polarization of stacking fault related luminescence in GaN nanorods

Abstract

Linear polarization properties of light emission are presented for GaN nanorods (NRs) grown along [0001] direction on Si(111) substrates by direct-current magnetron sputter epitaxy. The near band gap photoluminescence (PL) measured at low temperature for a single NR demonstrated an excitonic line at ∼3.48 eV and the stacking faults (SFs) related transition at ∼3.43 eV. The SF related emission is linear polarized in direction perpendicular to the NR growth axis in contrast to a non-polarized excitonic PL. The results are explained in the frame of the model describing basal plane SFs as polymorphic heterostructure of type II, where anisotropy of chemical bonds at the interfaces between zinc blende and wurtzite GaN subjected to in-built electric field is responsible for linear polarization parallel to the interface planes.