Space-resolved photoluminescence of ZnS:Cu,Al nanocrystals fabricated by sequential ion implantation

We report on photoluminescence (PL) properties of Cu- and Al-doped ZnS nanocrystals fabricated by sequential implantation of Zn+, S+, Cu+, and Al+ ions into Al2O3 matrices. The spatially resolved PL spectrum has been studied by a scanning near-field optical microscope (SNOM). In the SNOM image, bright spots are observed on the sample surface. The PL spectrum at each bright spot is broad and is not sensitive to the monitored positions. The broad SNOM-PL spectrum at each spot is very similar to the macroscopic PL spectrum measured by conventional optics. The donor-acceptor pair luminescence process in nanocrystals is discussed.