Fabrication of TiO2 nanotube on silicon substrate by two-step anodic oxidation for wafer level supercapacitors application

Abstract

In this paper, TiO2 nanotube arrays were tried to be fabricated on SiO2/Si substrates by using ultra weak anodic oxidation with two-step method. We investigated the influence of key parameters on the structure of the TiO2 nanotubes including potential, electrolyte and the oxidation time applied in two-step method. It is found that the morphology of the oxidized TiO2 nanotube arrays was strongly affected by the oxidation conditions. In the experiment, the titanium film with thickness of 400 nm was firstly sputtered on SiO2/Si substrates, and then low potentials of 10 V for 20 sec and 0.5 V for 25 min were respectively applied in HF solution with the low concentration of 0.05 wt%. The experimental results show that the dense TiO2 nanotubes with diameters ranged from about 90 to 270 nm with an average value of 150 nm were obtained in the two-step anodic oxidation method. The obtained TiO2 nanotubes with higher diameters are promising for manufacturing the micro supercapacitor with high specific surface area.