Structural analysis of sol-gel-derived LaNiO₃(100)/CeO₂(100)/Si(100) heterostructures

LaNiO₃(100)/CeO₂(100)/Si(100) as a metal/insulator/semiconductor heterostructure was prepared by a sol-gel method with a spin-coating technique. The structure of each oxide layer was investigated by out-of-plane and in-plane X-ray diffraction analyses. The high degree of {100}-orientation of the CeO₂ layers was obtained with higher heat treatment temperatures, 600-700°C. The in-plane measurements revealed that the CeO₂ layers had a nonepitaxial structure in Spite of the deposition on the Si (100) substrates with good lattice compatibility. The LaNiO₃ layers on the CeO₂(100)/Si(100) also exhibited the preferential {100}-orientation without epitaxy. The crystallinity of the {100}-oriented grains in the LaNiO₃ layers was higher than that in the CeO₂ layers. The occurrence of the orientation was discussed in view of the interracial energies at each interface.