Thermal stability of HfO2 nanotube arrays

▶ Highly ordered hafnium oxide nanotube arrays prepared through anodic oxidation. ▶ As-formed HfO2 nanotubes are amorphous and contain significant amounts of fluorine. ▶ HfO2 nanotubes are stable up to 700 °C in Ar. ▶ HfO2 nanotube morphology degraded at 900 °C in Ar. ▶ Dielectric permittivity values of HfO2 nanotubes are close to that of bulk literature values.