Atomic force microscopy examination of the evolution of the surface morphology of Bi4Ti3O12 grown by molecular beam epitaxy

The surface morphology of (001) Bi4Ti3O12 grown on (001) SrTiO3 by reactive molecular beam epitaxy (MBE) has been examined using atomic force microsco py (AFM). Initial nucleation of a 1/4 unit cell thick layer is followed by growth of 1/2 unit cell thick layers. Between 9 and 16 layers, a transition to 3-dimensional growth occurs, leading to well-defined mounds. This impli es a Stranski-Krastonov growth mode. During growth, the morphology follows a behavior consistent with the dynamic scaling hypothesis and we extract va lues for the scaling exponents alpha and beta from the AFM data. A thicknes s variation in alpha is observed and reflects the strain relief associated with the Stranski-Krastonov growth. (C) 1999 Elsevier Science S.A. All righ ts reserved.