Origin of Strong Photoluminescence Polarization inGaNP Nanowires.

The III–Vsemiconductor nanowires (NWs) have a great potentialfor applications in a variety of future electronic and photonic deviceswith enhanced functionality. In this work, we employ polarization-resolvedmicrophotoluminescence (μ-PL) spectroscopy to study polarizationproperties of light emissions from individual GaNP and GaP/GaNP core/shellNWs with average diameters ranging between 100 and 350 nm. We showthat the near-band-edge emission, which originates from the GaNP regionsof the NWs, is strongly polarized (up to 60% at 150 K) in the directionperpendicular to the NW axis. The polarization anisotropy can be retainedup to room temperature. This polarization behavior, which is unusualfor zinc blende NWs, is attributed to local strain in the vicinityof the N-related centers participating in the radiative recombinationand to preferential alignment of their principal axis along the growthdirection. Our findings therefore show that defect engineering viaalloying with nitrogen provides an additional degree of freedom totailor the polarization anisotropy of III–V nanowires, whichis advantageous for their applications as nanoscale emitters of polarizedlight. [ABSTRACT FROM AUTHOR]