INFLUENCE OF DEPOSITION TEMPERATURE ON THE STRUCTURAL AND OPTICAL PROPERTIES OF ELECTROCHEMICALLY NANOSTRUCTURED ZnO FILMS

The influence of the deposition temperature (in the range from 50 to 80 degrees C) of the aqueous solution containing ZnCl2 and KCl on the properties of ZnO films obtained by electrochemical deposition on SnO2 covered glass substrates is studied. Through the implementation of X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), UV-VIS-NIR and photoluminescence spectroscopy and optical profilometry, the temperature dependence of ZnO films properties is revealed. The polycrystalline status of the films is confirmed at all deposition temperatures through the obtained characteristic X-ray reflexes of the ZnO films. The SEM pictures show that the ZnO films deposited at lower temperature comprise nano-grains that transform in nano-walls with increasing the deposition temperature. With a further increase in temperature to 80 degrees C the deposited layers consist mainly of nano-rods. Further, it is demonstrated that the deposition temperature impacts the reflectance and transmittance spectra and haze ratio of the ZnO layers. The high values of the diffuse reflectance and transmittance in the spectral range from 350 to 800 nm could be beneficial for application of similar films as rear contacts of thin films solar cells.