Infrared Photoluminescence of Nd-Doped Sesquioxide and Fluoride Nanocrystals: A Comparative Study

Lanthanide ions possess various emission channels in the near-infrared region that are well known in bulk crystals but are far less studied in samples with nanometric size. In this work, we present the infrared spectroscopic characterization of various Nd-doped fluoride and sesquioxide nanocrystals, namely Nd:Y2O3, Nd:Lu2O3, Nd:Sc2O3, Nd:YF3, and Nd:LuF3. Emissions from the three main emission bands in the near-infrared region have been observed and the emission cross-sections have been calculated. Moreover, another decay channel at around 2 mu m has been observed and ascribed to the F-4(3/2)-> I-4(15/2) transition. The lifetime of the F-4(3/2) level has been measured under LED pumping. Emission cross-sections for the various compounds are calculated in the 1 mu m, 900 nm, and 1.3 mu m regions and are of the order of 10(-20) cm(2) in agreement with the literature results. Those in the 2 mu m region are of the order of 10(-21) cm(2).