Figure 5

PL decay properties of all the specimens. PL decay curves of the (a) Cu-Ar and (b) Cu-air specimens. Values of PL decay constants, and kinetic constants as a function of the Cu concentration of the (c) Cu-Ar and (d) Cu-air specimens. The excitation and monitored wavelength set 260Â nm and 440Â nm. Open squares and closed circles indicate first and second components of each PL decay constants and kinetic constants, respectively.