1. TiO2 thin films on nanoporous Alumina; fabrication and characterization
E. Kheirandish, T. Hosseini, N. Yavarishad, N. Kouklin Dept. of Electrical Engineering, Univ. of Wisconsin-Milwaukee

2. Overview
A large-area, electronic grade nanostructured TiO2 has many applications ranging from energy conversion and environmental uses.
In this study, a low-cost synthesis of columnar, microcrystalline TiO2 films was realized by sputtering on top of highly regimented nanoporous Al2O3 arrays produced by anodization of Al.

3. Columnar, microcrystalline TiO2 film
Fabrication of Al2O3 using anodization method
Sputtering Au on Al2O3
Sputtering TiO2  Anatase TiO2

4. Photoluminescence Spectrum

5. Temperature Dependent Transport
Activation energy ~ 0.1 meV

6. Conclusion
T-dependent transport, PL and Raman Spectroscopy  films remain electrically conductive, with primary mechanism being thermally-assisted free electron generation involving shallow donor-like defect states.
PL emission  weakly T-dependent ,spectrally broad as mainly controlled by several defect-assisted radiative recombination mechanisms as well.
This study opens a door to utilizing the sputtered films in DSSC, transparent electrodes and even light sensing/emitting devices.