Synthesis and characterization of heterostructured Mn₃GaN _0.5/GaN nanowires

Heterostructured Mn₃GaN_0.5/GaN nanowires have been synthesized by a catalytic chemical vapor deposition method. Mn ₃GaN_0.5/GaN nanowires exhibit ferromagnetic properties with a Curie temperature above room temperature. It was observed that the acceptor Mn²⁺/Mn³⁺ (Mn 3d) levels superpose on the GaN energy levels, shifting the energy of 5.8 eV toward Fermi energy. Compared with GaN nanowires, the D⁰X line of Mn₃GaN_0.5/GaN at 397.8 nm (3.117 eV) indicated the 33.4 nm red-shift due to hole-doping in the PL spectra. The synthesized Mn₃GaN_0.5/GaN nanowires had the relatively high yellow band emission of about 596.5 nm, due to the internal ⁴T₁→⁶A₁ transition of Mn ²⁺ (3d⁵), which is permitted by selection rules. The sharp peak at 675.6 nm in Mn₃GaN_0.5/GaN nanowire PL spectra might correspond to the transition ⁴T₂ → defect state.