Direct Synthesis of Lead Phosphate Thin Film with Monodispersed Pb Nanocrystals by Pulsed Laser Deposition

摘要

A thin film with monodispersed and well-crystallized Pb nanodots embedded in a lead phosphate glass matrix was prepared directly by a pulsed laser deposition technique. A 266nm beam from Nd:YAG laser with its power between 60 and 150mJ/pulse was irradiated at the transparent, massive target made from a mixture of P_O_5, PbBr_2 and PbCl_2 in a molar ratio 3:3:4. The nitrogen gas pressure in a reaction chamber was varied from 0.05Pa to 50Pa. The rate of deposition was constant at around 4nm/min. The average dot size, ca 6nm with its standard deviation well less than 10%, was rather insensitive to the species and temperature of the substrates, e.g. Si(100), poly(methyl methacrylate) or copper microgrid. Formation mechanism, size control and methods for better alignment were discussed.