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

Abstract

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.