Bursting of argon nanobubbles from Cu(100) subsurface induced by oxygen exposure and structural evolution

Abstract

Strain commonly exists in nanomaterials and may significantly influence the physico-chemical properties and local reactivities. Enhanced oxygen adsorption was reported to be induced by subsurface Ar bubbles [Gsell et al., Science 280, 717–720 (1998)] due to the alteration of local surface strain. In this work, we show a reverse effect wherein post-oxygen exposure induces the desorption of Ar from the subsurface of sputter-annealed Cu(100). The multiple desorption peaks, by the combined analysis of multiple techniques, are ascribed to the structural evolution (surface roughening and recrystallization) and strain release during oxygen exposure and subsequent annealing. Notably, the quantity of desorbed subsurface Ar exhibits a correlation with oxygen exposure. The thermal behaviors of subsurface Ar as well as the surface reactivities can thus be rationally regulated by the modification of the surface, demonstrating a new strategy to tune the physico-chemical properties of subsurface species.