Preparation, Chacteristics, And Properties Of TiO₂ Nanostructure And Nano N-TiO₂/p-diamond Heterojunctions

Titania (TiO2) is an important direct band gap semiconductor material. nanomaterials has recently attracted much attention due to its distinguished physical and chemical properties making it suitable for many applications such as photocatalysts, electron field emitter, photovoltaic cells, and chemical sensors.In this thesis, we prepare rutile TiO2 nanorods (NRs) on boron-doped diamond (BDD) film; synthesize anatase TiO2 nanotube (TiNT) arrays on chemical vapor deposited (CVD) BDD substrates and study their electrical and photocatalytic properties. The hollow and open-ended TiO2 nanosheets is fabricated on Si substrate and study their photocatalytic properties. Some innovative results are obtained and the details of our work are as follows:1. The rutile TiO2 NRs has been hydrothermally synthesized on BDD film with a ZnO buffer layer. It is proved that the ZnO buffer layer provide uniform heterogeneous nucleation sites effectively for the grown TiO2 NRs. Additionally, with the increase of reaction temperature and reaction time, TiO2 NRs exhibit a better crystallinity. The n-type TiO2 NRs/BDD heterojunctions have been prepared and the current-voltage (I-V) examination results represent a good diode behavior. Additionally, the TiO2 NRs/BDD heterojunction possesses better electron field emission performance with a low turn-on electric field and high current density.2. Anatase TiO2 nanotube (TiNT) arrays have been fabricated on a p-type boron-doped diamond substrate by a liquid phase deposition method using a ZnO nanorod template. It is proved that the ZnO nanorod template has important effect on the morphology of the TiNT. The n-typeTiNT/BDD heterojunctions have been prepared and the current-voltage (I-V) examination results represent a good diode behavior. The n-type TiNT/p-type diamond heterojunction structures which are realized show significantly enhanced photocatalytic activities with good recyclable behavior.3. The hollow and open-ended TiO2 nanosheets film is firstly fabricated on Si substrate. The TiO2 nanosheets are realized show good photocatalytic activities.