Comparative study of SnO2:Sb transparent conducting films produced by various coating and heat treatment techniques

Abstract

Transparent electrically conducting SnO2:Sb coatings have been prepared by the sol-gel dip-coating process from an ethanolic solution of SnCl2(OAc)2 and SbCl3 (5 mol%). The room temperature resistivity of the dip-coated films heat treated in a furnace or by laser IR irradiation is systematically greater than that obtained for films made by spray pyrolysis. Solution precursors and stabilisers and above all the deposition technique are the principal factors which influence the film morphology and hence the electrical properties. Single layers heat treated in a furnace are porous and consist of small, spherical shaped crystalline particles aggregated in a loose structure with a thin but denser top layer. A model of multilayers connected electrically in parallel allows us to determine the electrical parameters of the bulk and interface parts of the layers. Sintering by CO2 laser irradiation increases the particle size and the packing density resulting in a resistivity that is four times less than for the conventionally furnace heat treated samples.