SYNTHESIS AND INFRARED STUDY OF NANOSIZED ALUMINUM NITRIDE POWDERS PREPARED BY DIRECT-CURRENT ARC PLASMA

Nanosized hexagonal wurtzite aluminum nitride (AlN) powders have been synthesized by the direct current (DC) are plasma method using mixed g as of ammonia and nitrogen (NH3-N-2) The growth of the crystals is aff ected by the thermal stability of their nitric surface, and the averag e size of the particles varies slightly according to reaction gas pres sure. Fourier transform infrared (FT-IR) transmission measurements wer e carried out at room temperature on the nanosized powders in differen t mediums. The IR spectra show an intense and broad absorption peak at about 770 cm(-1) (epsilon(m)=2.36 of KBr) or 800 cm(-1) (epsilon(m)=1 .0 Of in air) attributed to the Frohlich mode of the nanostructured AL N crystals. Some bulk modes also appear as shoulders or peaks in the s pectra simultaneously.