Enhanced UV photo-detection properties of graphene oxide incorporated transparent TiO2 thin films in Schottky configuration

Here we report the modification of UV photo-response characteristics of solution processed transparent titanium dioxide-graphene oxide (TiO2-GO) nanocomposite thin films measured in metal-semiconductor (MS) Schottky junction configuration with the variation of GO content. Optical characterizations confirm the GO induced modification of optical band gap of TiO2 thin films of average thickness-100 nm without compromising the transparency in the visible range of electromagnetic spectrum. The nonlinear current-voltage characteristics with rectifying nature for TiO2-GO nanocomposite thin films with silver electrode indicate the formation of MS Schottky junction. The UV response characteristics like photocurrent, photo response times of the fabricated MS junctions improve significantly with the GO content in host TiO2 matrix when measured under UV light of wavelength-365 nm. The enhanced photocurrent (Iph) with reduced rise (tON) and recovery time (tOFF) of photo response is attributed to the GO induced modification of space charge region, passivation of interface defect states for betterment of charge carrier transport and less recombination of photo-generated charge carriers. Impedance spectra measured for nanocomposite thin films under dark and illumination confirm the modification of grain-boundary/interface to enhance the charge transport mechanism.