X-ray photoemission studies on rare gas bubbles in aluminium with annealing temperature

The annealing temperature dependence of the core-level spectra of the rare gas bubbles implanted in the sub-surface region of Al(111) has been investigated by x-ray photoelectron spectroscopy. A systematic change in the binding energy of the rare gas core-level has been observed, as a function of annealing temperature. The change in binding energy is explained by the increase in bubble size with annealing temperature. Al conduction electron screening of the rare gas core-hole decreases in the photoemission final state with increase in bubble size. We have also observed the decrease in concentration of the rare gas with annealing temperature. The Ne 1s spectra show two components separated by about 1.2 eV and change in intensity with temperature, which is possibly related to a near-surface and a sub-surface distribution of Ne bubbles. The near-surface component gets desorbed faster than the sub-surface component with annealing.