USE OF SUPERLATTICE STRUCTURE TO CONTROL REACTION-MECHANISM - KINETICS AND ENERGETICS OF NB5SE4 FORMATION

This paper presents a study of the reaction of thin film niobium/selen ium multilayers as a function of layer thickness. Diffraction and calo rimetry data show a distinct difference in reactions between films wit h layer thicknesses above and below 60 Angstrom. The thicker films are shown to nucleate Nb5Se4 heterogeneously at the niobium-selenium inte rfaces. Thinner films form kinetically stable amorphous reaction inter mediates before crystallizing Nb5Se4 homogeneously. The nucleation bar rier was measured using a Kissinger analysis demonstrating the kinetic stability of the amorphous intermediate. An energy versus reaction pr ogress diagram is presented that contrasts the two reaction mechanisms .