Structural and optical properties of ternary Cs-Pb-Cl nanoaggregates in thin films

Ternary nanophases of CsPbCl3 and Cs4PbCl6 were evidenced in co-evaporated CsCl-PbCl2 thin films using x-ray diffraction spectroscopy. A morphological study by atomic force microscopy revealed the granular nature of the films consisting of the grains of about 150 nm size. The optical properties of CsPbCl3 and Cs4PbCl6 nanostructures were determined. CsPbCl3 is a wide gap semiconductor with direct band transitions and a pronounced Wannier free exciton emission round 418 nm at 5 K with a very small Stokes shift. Cs4PbCl6 is characterized by the auto-localized exciton emission around 365 nm. In both cases, the optical features are closely similar to the bulk ternary crystals which were reported earlier. (C) 2001 American Vacuum Society.