Structural investigation of titanium oxide nanowires with unconventional optoelectronic behaviour.

Grazing incidence wide angle X-ray scattering measurements on aligned titanium oxide nanowires displaying anisotropic optical-electronic properties are carried out. Elemental and thermal analyses provide a chemical composition corresponding to H 2 Ti 3 O 7 · n H 2 O with n ≈ 1 while the crystallographic data indicate a monoclinic cell with a lamellar substructure. Cell parameters are close to those of H 2 Ti 3 O 7 notwithstanding a doubling of the lattice in the layer plane. A comparison of the band gap energy values and the electronic transition modes between the two polymorphs displays differences that could be ascribed to the structural variation.