Study of Nanoscopic Porosity in Black Metals by Positron Annihilation Spectroscopy

摘要

Black and smooth Al films were characterized by the variable energypositron annihilation spectroscopy (VEPAS). It was found that in smoothfilms positronium (Ps) is formed on the surface only while in black metalfilms, it is formed also in nanoscopic pores inside the film. The meanpore size increases from the substrate to the surface due to increasing filmroughness.