Gadolinium (Gd)- and gadolinium/magnesium (Gd/Mg)-films as well as top layers of catalytic films were prepared by rf-sputtering technique. To improve the optical properties, optical transparency, color and switching time, the Gd films were modified with Mg. By change of the sputtering parameters, the grain size of the Gd-films was varied in the range from 29 nm to 9.5 nm. To improve the catalytic properties, palladium-films (Pd) were modified with silver (Ag).
To investigate the influence of the structure and the microstructure on the optical and the switching properties of the films, X-ray diffraction measurements and scanning electron microscope studies were performed.
It is shown that the optical transmission of the GdH3 films can be improved by the modification of the gadolinium-films with magnesium. Further, a significant influence of the grain size is found. If the grains size of the films is reduced to 9.5 nm, the optical transmission of the films increases. The reduced grain size, leading to a larger inner surface, decreases the optical and the electrical switching time and the optical transmission. A reduction of the switching time is attained by the modification of the catalytic palladium films with silver.