Deposition of nanostructured thallium sulfide layers on organic and inorganic surfaces in a solution of higher polythionic acid
|Ingrida Bruzaite 2, Valentinas Snitka 1, Vitalijus Janickis 2|
1. Kaunas University of Technology, Research Center for Microsystems and Nanotechnology (RCMN KTU), Studentu 65 - 203, Kaunas 3031, Lithuania
Materials with three-dimensionally periodic structures have attracting considerable attention over the last decade. These materials have the potential for use as photonic materials, advanced catalysts, sensors. Thallium sulfides electrical conductivity changes with exposure to light, therefore making this compound useful in photocells and sensors.Thalium sulfide layers with different composition on the surface of polyethylene were obtained when this polymer firstly have been sulfured in a solution of higher polythionic acid, H2S33O6, and then treated with alkaline solution of thallium(I) sulfate.
In this work we investigate the growth of nano-structured thalium sulfide thin films on the surface of organic (polyethylene), inorganic (LiNbO3) and matrix (silica-polystyrene latex) substrates. Silica films containing three dimensionally (3D) ordered polystyrene latex (PSL) nano-beads were prepared by dip coating method. Silica sol-gel films derived from tetraethylorthosilicate (TEOS) containing polystyrene latex beads with diameter 50 nm and 200 nm and were used for the nano-ordered thallium sulfide dots deposition. The stoichiometric composition of thallium sulfide layers varies between Tl0.3S and Tl2.6S in dependence on the conditions of the formation of the layers of TlxSy. A phase composition of the layers obtained was confirmed by the method of X-ray photoelectron spectroscopy. Spectra of Tl 4f7/2, O 1s and S 2p showed the bond of thallium with sulfur in TlS and Tl2S , but Tl2SO4, Tl(OH)3, S8 and Tl2O3 have been also found in the surface of the layers. The investigation of the film growth mechanism on different substrates by Scanning Atomic Force Microscopy revealed that the sorbtion-diffusion on the surface dominate the formation of the TlxSy crystallites formation. The photoconductivity of the films was investigated by the structure of planar electrodes and radiation by UV light.
Presentation: oral at E-MRS Fall Meeting 2005, Symposium F, by Ingrida Bruzaite
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-06-05 17:29 Revised: 2009-06-07 00:44