Synthesis, Magnetism and Photoluminescence of Mn Doped AlN Nanowires

Manganese doped aluminum nitride (AlN:Mn) nanowires were fabricated by direct nitridation of Al and Mn mixed powders. The as-synthesized AlN:Mn nanowires were characterized by X-ray diffraction, Raman, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy. The measurements reveal the successful incorporation of Mn2+ ions into AlN nanowires. The magnetic and optical properties of the AlN:Mn nanowires were studied using vibrating sample magnetometer and photoluminescence spectroscopy. The AlN:Mn nanowires exhibit room temperature ferromagnetic behavior and a red emission band centered at 597 nm corresponding to the 4T1(4G)-6A1(6S) transition of Mn2+. The abnormal thermal quenching behavior and long afterglow feature are investigated through the temperature dependent emission and the afterglow spectrum. The thermoluminescence curve shows that AlN: Mn nanowires have a wide trap distribution, which leads to the abnormal thermal quenching behavior and persistent luminescence. Multifunctional AlN:Mn nanowires with magnetic and luminescence properties are expected to be used in spintronic and optoelectronic nanodevices.

Recycling of the Diamond-wire Saw Powder by Ni-catalyzed Nitridation to Prepare Si3N4

In this paper, the acceleration of nickel (Ni) in the direct nitridation process of the diamond-wire saw powder (DWSP) was investigated. The DWSP doped with Ni additives were nitrided at different temperatures. To study the mechanism of accelerated nitridation, the thermodynamics of Si-O-N-Ni was analyzed by FactSage 7.2 and single-crystal silicon blocks were also nitrided instead of the DWSP. The results revealed that Ni decreased the nitridation temperature at which the DWSP began to gain significant weight and exhibited an excellent accelerating effect on the nitridation of the DWSP. At 1300℃, the DWSP containing 2.0 wt.% Ni additives had been completely nitrided within 2 h, whereas the DWSP without Ni additives had not been nitrided yet. Based on the equivalent substitution experiment, it could be conducted that the presence of Ni additives accelerated the nitridation and promoted the formation of the α-Si3N4 nanorods through facilitating the generation of the SiO(g) and destructing the silica film on the surface of silicon at lower temperature. Meanwhile, Ni additives also played an important part in the growth of α-Si3N4 nanorods by forming liquid Ni-Si alloy in the product.