Optoelectronic properties of SnO2 / TiO2 junctions

Transparent, conductive SnO2 (FTO) films and colloidal TiO2 films deposited on these FTO films are investigated by means of contactless transient photoconductance measurements in the microwave frequency range (TRMC measurements). For the bare FTO-glass films excitation with 355 nm light pulses leads to appreciable TRMC signals indicating the semiconductor properties of the material. For TiO2 films on FTO-glass films, injection of excess electrons from TiO2 into FTO is observed.