Aligned TiO₂ nanorods and nanowalls

Well-aligned rutlie and anatase TiO₂ nanorods as well as anatase TiO₂ nanowalls have been synthesized using a template- and catalyst-free metalorganic chemical vapor deposition (MOCVD) method. Structural analyses indicate that single-crystalline rutile and anatase TiO₂ nanorods were formed at 630°C and 560°C, respectively, while anatase TiO₂ nanowalls composed of well-aligned nanorods were formed at 535°C. Optical characterizations of these TiO₂ nanostructures show that the band gap energies for indirect transition of the rutile TiO₂ nanorods and anatase TiO₂ nanorods as well as nanowalls are at 3.0 and 3.2 eV, respectively.