Effect of in situ annealed SnO₂ buffer layer on structural and electrical properties of (0 0 1) SnO₂/TiO₂ heterostructures

We have studied heteroepitaxial growth of SnO₂ films on (0 0 1) TiO₂ substrates by pulsed laser deposition. In order to reduce crystalline defects arising from a large lattice mismatch (3.1%), a SnO₂ buffer layer is employed. The buffer layer prepared by in situ annealing under optimized conditions exhibits an atomically flat surface and partially relaxed lattice, which play an important role in the improvement of crystallinity and electrical properties for the overgrown layer. The results are discussed based on the structural characterization by means of x-ray diffraction and transmission electron microscopy and temperature dependence of Hall mobility.