Evolution of dislocation arrays in epitaxial BaTiO3 thin films grown on (100) SrTiO3

Dislocation arrays and dislocation half-loops in BaTiO3 thin films were characterized using transmission electron microscopy (TEM). BaTiO3 films with thicknesses ranging from 2 to 20 nm were grown on (100) SrTiO3 by reactive molecular beam epitaxy (MBE). The critical thickness for dislocations to occur in this system was found to lie between 2 and 4 nm. The misfit dislocations are mainly <100> type. The average spacing between the dislocations in the array becomes smaller when the film is thicker, which indicates gradual relaxation of mismatch strain with increasing film thickness