Fig. 3: Growth mode and strain relaxation of remote epitaxial BTO films.

AFM images of BTO films grown with different equivalent thicknesses: a 0.3 nm; arrows mark two of the separated islands and the wrinkle serving as the nucleation center was denoted; b 3 nm, c 10 nm, and d 90 nm. The schematic illustration of the film growth process: e Three-dimensional epitaxial islands nucleation following the Volmer-Weber mode, corresponding to a; f islands coalescing, corresponding to b; g and h formation of a flat film, corresponding to c and d. i Evolution of the lattice parameter as a function of the film thickness. The error bars are defined by the peak fitting of the XRD results shown in Fig. S15. j Evolution of the c/a ratio (lower) and lattice volume (upper) as a function of the film thickness. The error bars were calculated based on the results in i.