Group V transition metal-based mixed nitrides formed by nanoscale reactive ion beam mixing of interfaces

► Growth of Nb- and Ta-based mixed nitrides by nanoscale reactive ion beam mixing of interfaces. ► Kinetics of growth, composition and electronic structure of the films studied by XPS and UPS. ► A reactive ion beam mixing kinetics of three stages has been found by factor analysis. ► In the third stage, stoichiometric nitride species are transformed into mixed nitride species. ► During this transformation, a metal-to-insulator transition is observed in the UPS valence band.