ZrO2 films deposited by spray pyrolysis from water-based precursor solutions on glass and TCO substrates

Abstract

This thesis focuses on gaining a better understanding of depositing stable ZrO2 layers on transparent conducting oxide substrates while using spray pyrolysis from water-based precursor solutions. ZrOCl2×8H2O was chosen – out of curiosity – as the precursor salt for the process. The influence of a range of factors, that play an important role for the spray-pyrolysis process, were studied on three substrates: borosilicate glass, fluorine doped tin oxide (FTO) and tin doped indium oxide (ITO). The precursor concentration was varied between 25mM and 100mM to investigate the behaviour of the ZrO2 films on the chosen substrates. The scanning repetitions were varied between 75 and 250 to analyse the evolution of crystallisation as the ZrO2 thickness increased. The temperature of the heating surface was tested between 360°C and 430°C to see its impact on the crystallin character of the films.The crystal structure, morphology and transmission of the obtained layers were evaluated by scanning electron microscopy, X-ray diffraction and Fourier-transform spectroscopy.Due to shortcomings it was only partly possible to obtain crystallin ZrO2 films. Despite the clearly visible formation of cubic zirconium oxide on all samples, the morphological investigation indicates the impact of droplets in its major part, which is not ideal for a vapour phase dependant process. Further optimization of the chosen process and precursor salt is necessary to obtain a successful receipt in order to implement it in further applications such as solar cells or optoelectronic devices.