Formation of TiO₂ and ZrO₂ nanotubes using atomic layer deposition with ultraprecise control of the wall thickness

The nanotubes of TiO₂ and ZrO₂ with diameters of ca. 30-200 nm were developed using atomic layer deposition (ALD). The was done at temperature of 140 °C followed by chemical etching of the polycarbonate (PC) template. A high aspect ratio of 60:1 was achieved in both oxide nanotubes. Contact-printed OTS-SAMs were found to prevent deposition onto both sides of the PC templates which in result allowed the free-standing TiO₂ and ZrO₂ nanotubes. The results show that the nanotubes with ultraprecisely controlled inner diameters can be utilized in the fabrication of coaxial quantum cables in nanoelectronics.