Photoelectrical properties of nitrogen doped TiO2 nanotubes by anodic oxidation of N+ implanted Ti foils

• Nitrogen ions were doped by the method of ion implantation.
• N+ implantation is beneficial to the formation of TNTs.
• Visible light induced photocurrent was appeared on the implanted samples.

Ti foils were implanted by N+ with accelerating voltage of 60 kV. The dose of implantation was chosen as 1×1016, 1×1017 and 5×1017 ions/cm2 respectively. N-doped TiO2 nanotubes (TNTs) were produced by anodic oxidation method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to study the structural and chemical properties of TNTs. The photocurrent of TNTs under both UV and visible light irradiation was measured and recorded in situ using an electrochemical station. The results showed that N-doped TNTs displayed strong absorption remarkably in both UV and visible range. Not only the separation efficiency of photo-generated electron–hole pairs of N-doped TNTs was improved, but the absorption edge of the samples was shifted to longer wavelength for the implantation. The best implanted dose with premier photocurrent was 1×1017 ions/cm2 under both UV and visible light irradiation.