Quasi‐Aligned Single‐Crystalline W18O49 Nanotubes and Nanowires

Quasi‐aligned W 18 O 49 nanotubes and nanowires with single‐crystalline monoclinic structure were prepared via a physical vapor deposition process. The axes of the nanotubes and nanowires were aligned along the [010] direction. Field‐emission measurement revealed a threshold field of 6.2 V μm –1 for W 18 O 49 nanowire films, indicating the prepared W 18 O 49 nanowires are excellent field emitters.