Laser-induced metal cluster growth and segregation in granular metal-insulator systems

We report on laser-induced segregation and growth of Au clusters in binary Au-TeO2 cermetlike thin films. Besides nanosecond-time-resolved reflectivity and transmissivity studies, structural and compositional transformations were investigated by conductivity, Rutherford backscattering, x-ray photoemission depth profiling, x-ray diffraction, and cross-sectional transmission electron microscopy measurements. Our results indicate that the laser irradiation, above a threshold fluence, induces melting of the thin film leading to growth, segregation, and coalescence of Au crystallites in the amorphous TeO2. These changes in the film microstructure are responsible for the optical and electrical modifications observed. © 1986 The American Physical Society.