Figure 3: FE-SEM image of close-packed AlN nanowires obtained by chemical conversion of the alumina nanowires shown in Fig. 2.Scale bar2 μm

Mentions: Figure 3shows a typical FE-SEM image of the above-described nanowires converted at 1,300–1,400 °C in ammonia atmosphere. It can be seen from the figure that the converted nanowires are still with closely packed arrangement, but their morphology is obviously different from that of the starting alumina ones. It is noted that the converted nanowires have a diameter of 15–20 nm, which is obviously larger than that of the unconverted ones. Figure 4gives the corresponding XRD spectrum of the converted nanowires. The XRD result shows that the converted nanowires are mainly hexagonal wurtzite phase of AlN (Ref: PDF card of No. 25-1133) but a small quantity of α-Al2O3phase. This indicates that most of the alumina nanowires have been converted into the AlN nanowires during heat treatment.

Bottom Line: The resultant alumina nanowires were reacted with NH(3) and evaporated aluminum at an elevated temperature to be converted into densely packed aluminum nitride (AlN) nanowires.The AlN nanowires have a diameter of 15-20 nm larger than that of the alumina nanowires due to the supplement of the additional evaporated aluminum.The results suggest that it might be possible to prepare other aluminum compound nanowires through similar process.

Abstract: Porous alumina film on aluminum with gel-like pore wall was prepared by a two-step anodization of aluminum, and the corresponding gel-like porous film was etched in diluted NaOH solution to produce alumina nanowires in the form of densely packed alignment. The resultant alumina nanowires were reacted with NH(3) and evaporated aluminum at an elevated temperature to be converted into densely packed aluminum nitride (AlN) nanowires. The AlN nanowires have a diameter of 15-20 nm larger than that of the alumina nanowires due to the supplement of the additional evaporated aluminum. The results suggest that it might be possible to prepare other aluminum compound nanowires through similar process.