Photoluminescence properties of single Mn-doped CdS nanocrystals studied by scanning near-field optical microscopy

We have fabricated Mn-doped CdS (CdS:Mn) nanocrystals embedded in Al(2)O(3) matrices by sequential ion implantation and studied their photoluminescence (PL) properties by a scanning near-field optical microscope (SNOM). In the PL spectra of CdS:Mn nanocrystals measured by the SNOM, several sharp PL lines and a broad PL band were observed. The sharp PL lines are related to bound excitons at shallow impurities in CdS nanocrystals. The Mn-related PL spectrum is very broad even in single nanocrystals at low temperatures, and both the peak energy and the spectral width of the PL band depend on the excitation laser intensity. The PL properties of single CdS:Mn nanocrystals are discussed. (C) 2005 American Institute of Physics.