Effects of TiO₂ Nanorod Length and Post-Annealing on the Electrical Properties of TiO₂ Nanobarbed Fiber Structures

TiO₂ nanobarbed fiber (NBF) structures consisting of TiO₂ nanorods (NRs) on TiO₂ nanofibers (NFs) were fabricated. The mean length and diameter of the TiO₂ NRs grown for 6 h was 1.38 μm and 71 nm, respectively. One NR was connected to other NRs and the junction points between the TiO₂ NRs increased with increasing TiO₂ NR length. The crystal structure of the TiO₂ NFs and NRs was rutile and anatase, respectively. After post-annealing, only the intensity of the TiO₂ NBF peaks increased without any significant structural changes. Raman spectroscopy showed that the TiO₂ NBF structure consisted of anatase (TiO₂ NFs) and rutile (TiO₂ NRs). The bandgap of the TiO₂ NBF structure prepared during a TiO₂ NR growth time from 0 to 6 h decreased from 3.23 eV to 3.10 eV. The conductivity of the TiO₂ NBFs with longer NRs was enhanced by post-annealing.