Structural evolution of nanostructured YBa_2Cu_3O_x thin films formed by pulsed laser glancing angle deposition

摘要

Nano-structured thin films of amorphous YBa_2Cu_3O_x were prepared by pulsed laser glancing angle deposition. Ambient oxygen pressure and laser fluence have a strong effect on the microstructure of the films. The films exhibit a structural evolution from isolated nanorods, through network of vertical nanocolumns, to nanoparticles fractal with increasing ambient oxygen pressures. Shadowing effect, surface diffusion and flux scattering by ambient gas play main roles in determining the structural evolution.