Characterization of Spin-Coated Terbium-Doped Strontium Cerate Thin Film Membranes

Abstract

In this article we present the synthesis and characterization of thin film membranes based on a ceramic oxide system with a perovskite structure, which is of interest in the development of solid oxide fuel cells (SOFCs) and hydrogen (H 2 ) separation membranes. Continuous and homogenous dense thin film membranes of terbium-doped strontium cerate (SrCe 0 . 9 5 Tb 0 . 0 5 O 3 - 8 ) have been prepared from ethylene glycol-based polymeric precursors using spin-coating technique. The Polymeric precursors have been deposited on silicone-based substrates and converted to dense polycrystalline metal oxide films after a sequence of annealing treatment at relatively low temperatures (400°C). Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) techniques are used to characterize the polymeric precursor chemistry and to confirm the perovskite structure of the calcined thin films respectively. The effect of sintering temperature and number of spin-coating cycles on the surface morphology and film thickness of the calcined thin films have been studied systematically using scanning electron microscopy (SEM) and focused ion-beam (FIB) milling techniques respectively. The surface chemistry of the thin membranes has been revealed using the x-ray photoelectron spectroscopy (XPS) analysis. FIB cross-section images indicate that thin membrane films having varying thicknesses within the range of 200 nm-2 μm can be effectively produced by controlling the number of spin-coating cycle combined with the proper drying and annealing cycles after each individual coating-step.