Synthesis and optical properties of aluminum nitride nanowires prepared by arc discharge method

AlN nanowires with hexagonal structure were successfully synthesized by direct reaction of aluminum with nitrogen gas using arc discharge method. The wurtzite AlN nanowires have an average diameter of 40 nm and a length of several tens micrometer. The growth direction of most single-crystalline AlN nanowires is perpendicular to the [0 0 1] direction, while it is also found that the AlN nanowires grow along [0 0 1] direction. The vapor–solid growth mechanism can explain the formation of the AlN nanowires. Raman spectroscopy studies of the AlN nanowires reveal that the stress is rather low and the crystallinity is close to bulk AlN. The UV spectrum of the AlN nanowires shows that the absorption edge at 6.23 eV is comparable with that of the bulk AlN. The photoluminescence of the AlN nanowires suggests that the emission band at 506 nm may be ascribed to the deep level defect due to nitrogen vacancy.