Optical properties of GaN and GaMnN nanowires grown on sapphire substrates

The authors discussed the photoluminescence (PL) spectra of GaN and GaMnN nanowires grown on sapphire substrates. Comparison of the excitonic PL peak energy with bulk GaN indicates that the strain of the nanowires is fully relaxed. For GaMnN nanowires, the redshift of the PL peak with increasing temperature was larger than that of the GaN nanowires, which was explained by redistribution of carriers into localization sites. The absence of Zeeman shift and circular polarization in GaMnN nanowires indicates that the exchange interaction between carriers and Mn2+ has to be at least one order of magnitude smaller than that in Cd0.94Mn0.06S nanowires.