Study of ZrO2 nanolayers deposited electrochemically on different conductive substrates

Abstract

Studies are presented of electrochemically deposited nanostructured layers of ZrO2 on different conductive substrates using a thermostatic bath with a three-electrode cell as an electrochemical system. The aqueous solution in the system contained ZrOCl2 and KCl. The layers' structural properties were determined by X-ray diffraction (XRD), with the spectra revealing the polycrystalline nature of the layers with the typical characteristic reflexes of ZrO2 for all substrates studied. The average grain sizes (between 39 nm and 121 nm) were determined from the diffraction patterns for each crystallographic axis associated with a maximum. Morphological investigations by scanning electron microscopy (SEM) and optical profilometry were also carried out and the average roughness of the layers was calculated. The structures' optical properties were determined by UV-VIS-NIR and photoluminescence spectroscopies. The influence of the substrates on the ZrO2 layers’ specular and total reflectance is presented and discussed. The excitation wavelength of photoluminescence spectra was 235 nm, with all samples exhibiting broad emission bands with peaks centered within the 410–430 nm range. The diffuse reflection showed high values in the spectral range 350–800 nm. Such layers are promising candidate as rear contacts of thin-film solar cells.