structural and opto-electrical analysis of Cu doped ZnO thin films by sol-gel method

Copper-doped zinc oxide thinfilms, (1, 3,5 at. %) have been synthesized via sol-gel spin coating technique. Main objectives of the reported -work are to investigate the effect of copper doping on morphology, compositional, structure and on opto-electrical properties of ZnO thin films. To achieve the mentioned objectives, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), X- Ray Diffraction (XRD), UV-vis techniques and the current-voltage (I-V) measurements -were performed. SEM result show a porous morphology. The % Cu concentration, determined by EDX analysis, are 0.66%, 3.73% and 6.26% in good agreement with the Cu theoretical concentration. XRD analysis shows that the films are nanocrystalline zinc oxide with the wurtzite structure. From optical measurements, a significant decrease in average optical transmission from 93 to 76 % is observed for all doped samples and the band gap value decreased from 3.20 to 3.00 eV which are related to the presence of defects due to Cu incorporation. The resistivity value of 9.64Ω10 ^-4 Ω-cm have been achieved -which is very promising in electronics for field effect transistors.