Preparation and characterization of epitaxially grown yttria-stabilized zirconia thin films on porous silicon substrates for solid oxide fuel cell applications

Epitaxial growth of yttria-stabilized zirconia (YSZ) thin film on through-hole-type porous silicon [tht-PSi(001)] with vertical pores penetrating from the surface to the back side of the Si(001) substrate was achieved. The inplane and out-of-plane lattice parameters of YSZ thin film deposited on the tht-PSi(001) were, respectively 0.5167 and 0.5124 nm. Therefore, 0.54 % tensile strain was applied to the YSZ thin film. Also for this work, an all epitaxially grown thin film of YSZ/La0.7Sr0.3MnO3 (LSMO)/CeO2/YSZ/Si(001) was prepared. The out-of-plane lattice parameter of YSZ was 0.5145 nm. Therefore, the YSZ thin film of YSZ/LSMO/CeO2/YSZ/Si(001) is almost relaxed, with a small amount of tensile strain (0.12 %). In-plane and out-of-plane electrical properties were measured respectively for YSZ/tht-PSi(001) and YSZ/LSMO/CeO2/YSZ/Si(001) thin films. Results show that ionic conduction was confirmed at 400 degrees C through constant electric conductivity against the change of oxygen partial pressure (pO(2)). Enhanced ionic conduction was observed for epitaxial YSZ/tht-PSi(001) thin films measured along the in-plane direction. Such enhanced ionic conduction was not observed for epitaxial YSZ/LSMO/CeO2/YSZ/Si(001) thin films measured along the out-of-plane direction. These findings suggest that enhanced ionic conduction is correlated with tensile strain in YSZ thin films. (C) 2022 The Ceramic Society of Japan. All rights reserved.

Automated summary

Epitaxial growth of yttria-stabilized zirconia (YSZ) thin film on through-hole-type porous silicon (tht-PSi(001)) was achieved, and the strain applied to the YSZ thin film was found to affect the ionic conduction.