Abstract

We assess the linearity between the reduction of the optical transmittance in the wavelength range of 600–1000 nm and the hydrogen concentration in Cr/V hydrogenated superlattice structures, with a nominal Cr/V ratio of 2/14. The V layers, contained inside an epitaxial Cr/V superlattice, were exposed to gaseous H atmosphere. The hydrogen uptake, as well as the changes in their optical properties, due to the hydrogenation, were monitored through optical transmittance measurements. The resonant 1H(15N,αγ)12C nuclear reaction was used to obtain the hydrogen depth profile and to determine the average hydrogen concentration per host atom in the V layers. Linearity was experimentally confirmed between the change in optical transmittance in a wide wavelength range and the H concentration, showing that optical data can be used to extract the relative hydrogen concentration. Additionally, the changes in the optical transmittance of the superlattice were found to be more pronounced for incident light with a wavelength of 600 nm, while the corresponding optical changes in the wavelength range 700–1000 nm, presented negligible dependence on the wavelength.