Growth of Ge islands on SrTiO3 (001) 2 × 1 reconstructed surface: Epitaxial relationship and effect of the temperature

The structural properties of Ge islands grown by molecular beam epitaxy on SrTiO3 (001) substrates are investigated. We report on the effect of the temperature on the epitaxial relationship and morphology of the Ge islands. By combining X-ray diffraction measurements and atomic force microscopy we evidence a correlation between the island size and shape, the structural properties of the interface and the sample texture. In particular, we show that the growth temperature affects the nature of the interface between the semiconductor and the perovskite oxide and thus the island orientation, that evolves from fully (001) oriented to a mixture of (111) and (001) oriented islands.