Effect of doping on microstructure and optical properties of ternary structure of Zn_1−x−yB_xC_yO (B=Cu, C=Co) nano thin films

We report the results of an in depth study of optical and microstuctural properties of thin films of Zn_1−x−yCu_xCo_yO system (x = 0,00 and 0.02, y = 0.00, 0.01, 0.02, 0.03, 0.04. and 0.05) which are grown by the sol–gel method. We have performed differential thermal analysis, and thermo gravimetric analysis/difference thermogravimetric analysis, x-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, atomic force microscopy and UV–VIS spectrophotometer experiments. We have found that all of the studied samples are in hexagonal wurtzite structure and oriented along the (002) direction with a very weak signal for the (101) reflection. We have also found that the lattice parameter c increases with doping. All the films showed wrinkle network structure with nano-sized crystals and the grain size was observed to decrease with increasing Co doping. The bandgap was found to decrease from 3.28 to 3.22 eV with doping. All the above results will be discussed in detail.