Nano-crystalline TiO2 thin film: Synthesis and investigation of its optical switching characteristics

Optical-switching property of nano-crystalline TiO2 thin films of thickness ~ 100 nm synthesized using sol-gel assisted spin coating method on ~ 0.14 mm thick Al substrate were investigated in this work. The structural analysis of TiO2 thin film show its polycrystalline nature with anatase phase. Surface analysis of the film via scanning electron microscopy and atomic force microscopy show rough TiO2 surface with nearly crack free surface. Current-voltage measurement carried out on this sample (Pt/TiO2/Al) in dark and under optical illumination show enhancement in dark current under optical illumination resulting from photo generation of charge carriers in TiO2 thin film. In addition to this, it also gives rise to optical-switching in the current from low to high and high to low as the illumination was ON and OFF. These results suggest that nano-crystalline TiO2 thin film based optical-switching devices have potential for integrating current device technology towards exciting photo-active device technology.