Josephson effect in TiO2 nanostructured films

High resistivity TiO2 nanostructured films exhibit photovoltaic dc voltages within the range 1–10 mV with strong sensitivity to low energy radiation. Close similarities of these dc photovoltages with those related to Josephson coupling in granular films and high-Tc cuprates suggest large infrared photon absorption with pair transitions between superconducting grains. We give theoretical support to the existence of a high-Tc state within the TiO2 grains which can be the basis of resonant radiation absorption through Josephson intergrain coupling.