Novel Sn powder preparation by spark processing and luminescence properties

We have prepared nanosize Sn powders by spark processing. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to study the morphologies and sizes of these powders. Furthermore, X-ray diffraction (XRD) analyses are performed on spark processed Sn (sp-Sn) powders. Spark processed Sn powders are spherically shaped particles with diameters in the range of 3-5 nm. The photoluminescence characteristics of nanosized Sn powders are examined at various temperatures. In addition to the luminescence peak of 2.06 eV originating from SnO2, the photoluminescence studies of sp-Sn at room temperature and low temperature reveal an additional high-energy emission band in the violet range (2.95 eV). The violet PL band exhibits a continuous blue shift and shows an increase of PL intensities with decreasing temperature. These experimental results indicate that the violet PL band of sp-Sn powders may have originated from quantum size effects. (C) 2002 Published by Elsevier Science B.V.