Morphology and structure of defected niobium oxide nonuniform arrays formed by anodizing bilayer Al/Nb systems

The work is devoted to the X-ray diffraction research of defected niobium oxide nonuniform (NON) arrays and niobium oxide nanocolumns formed by electrochemical anodizing. The obtained results allow to make an assumption about the probable presence of a significant amount of NbO, NbO$_{0.7}$, Nb$_{2}$O$_{5}$ and a small amount of NbO$_{2}$, and Al in the composition of defected NON and the presence of all these substances in the nanocolumns of niobium oxide except NbO$_{0.7}$, but in smaller quantities. The comparative analysis of the NON structure and the nanocolumns makes it possible to isolate, probably, a significant amount of Nb$_{0.94}$O$_{0.06}$, Nb$_{6}$O in the defected nanocolumns, which was not found in NON.