We have investigated the possibility of Ag photodoping into crystalline (c-) ZnSe grown by molecular-beam epitaxy. A Ag/c-ZnSe sample was illuminated with a 325 nm HeCd laser at 10 K and its photoluminescence (PL) characteristics were measured in real time. Depending on the illumination time, there are considerable changes in the intensities of the deep-level peaks (2.059 and 2.345 eV) as well as the near-band-edge peak (2.798 eV). The emission band at 2.059 eV is almost independent of PL-excitation power, while the green luminescence band at 2.345 eV exhibits distinctly a power-dependent blueshift with increasing excitation power, which can be assigned as a donor-to-acceptor pair transition (Ag_(i)Ag_(Zn)). In this letter, a model to explain Ag photodoping into c-ZnSe is proposed on the basis of the PL results. We believe that Ag, as an activator for luminescence, can be photodoped into c-ZnSe even though the extent and kinetics of the Ag doping are different from those of the amorphous chalcogenide.
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