Modification of the structural properties of niobium thin films after hydrogenation

The relationships between the concentration of hydrogen absorbed in thin films of Al$_2$O$_3$//Nb type and the structural properties of these films have been established. The main research methods were X-ray diffraction and reflectometry. Structural changes after hydrogenation processes at various temperatures are analyzed. The hydrogenation conditions under which solid solutions of hydrogen in niobium and/or niobium hydrides are formed are specified. It is shown that it is possible to additionally control the concentration of hydrogen in niobium by applying a graphene layer to the film surface, obtaining an Al$_2$O$_3$//Nb/Gr type system. Being a kind of “anticatalytic layer”, graphene significantly slows down the penetration of hydrogen into the sample, which makes it possible to obtain the necessary concentrations with high accuracy.