Solid State Ionics, Vol.302, 165-172, 2017
Investigation of microstructure and electrical properties of Sm doped ceria thin films
Sm0.2Ce0.8O2-delta (SDC) thin films (similar to 1.9 mu m) were deposited on SiO2, Alloy 600 (Fe-Ni-Cr), and A1203 substrates, using e-beam evaporation technique. The deposition rate was 0.2 nm/s =1.6 nm/s, and substrate temperature during the formation of thin films was kept 323 K, 423 K, 573 K, 723 K and 873 K. SEM analysis reveals that grain size increases at 323 K, 423 K, and 573 K substrate temperatures and decreases at 723 K and 873 K temperatures. The preferential out-of-plane orientations of thin SDC films were (111) and (222). Texture coefficients of those orientations decrease at high deposition rates (12 nm/s and 1.6 nm/s) and high substrate temperatures (723 K and 873 K). The preferential orientation changes to (220) or (222) using SiO2 sub' strates (1.2 nm/s and 1.6 nm/s growth rate; 423 K, 723 K, and 873 K substrate temperature) and to (200), (220), or (311) using Alloy 600 substrates (0.2 nm/s, 0.8 nm/s, 1.2 nm/s, and 1.6 nm/s deposition rate; 723 K and 873 K substrate temperature). Crystallite size increases from 6.8 nm td 80.6 nm with increasing substrate temperatures (323 K divided by 873 K) and influences total conductivity of SDC thin films; it increases (0.03.10(-3) S/m 1.12 S/m) with increasing crystallite size. Ce3+ concentrations change from 24.5% to 29.1% in thin SDC films and do not show clear correlation with changes of total conductivity. In addition, thin films deposited at 323 K divided by 423 K temperatures and 0.4 nm/s divided by 1.6 nm/s deposition rates have reduced total conductivity. (C) 2016 Elsevier B.V. All rights reserved.