Sol-gel deposition and characterization of multilayer 2% Cu doped TiO2 nano structured thin films

Multilayer of 2% Cu doped TiO2 thin films have been grown by sol-gel spin coating on glass substrate in the form of three, five and seven layers. X-ray diffractrometer (XRD) confirms the doping of Cu into TiO2. Scanning electron microscopy (SEM) confirms the formation of nano particles with average size of 19, 25 and 35 nm for three, five and seven layers of thin films, respectively. The electrical resistivity of these multilayer films is found as 2.19 x 10(7), 1.20 x 10(7) and 1.11 x 10(7) ohm-m respectively. UV-vis shows that the films have 80% transmittance in the visible region which is good for solar spectrum. The optical band gap energy decreases with an increase in the number of layers as 3.778, 3.768 and 3.736 eV respectively for 3, 5 and 7 layered thin films. This work provides an environment friendly and low cost use of an abundant material for optoelectronic devices.