GROWTH OF NANOCRYSTALLINE PBS WITHIN A GLASS

Nanocrystalline PbS has been grown within a phase-separated oxide glas s of composition 10 Na2O, 15 PbO, 17 CaO, 3 Bi2O3, and 55 SiO2 (in mol e %) by passing H2S gas over it at temperatures varying from 773 to 94 3 K. The particle size ranged from 2.5 to 12.9 nm. The dc resistivity of composites of nanocrystalline PbS and the phase separated glass has been measured over the temperature range 300 to 670 K. The resistivit y variation in the temperature range 550 to 670 K is characterized by the sodium ion migration in the glass with an activation energy simila r to 1.2 eV. The resistivity in the range 300 to 500 K was controlled by conduction in PbS particles with the estimated band gap showing an increase with a decrease in the particle size.