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 microm 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.