Substrate influence on preferential orientation of Bi2Te3 layers grown by physical vapor transport using elemental Bi and Te sources

Abstract Physical vapor transport growth of Bi 2 Te 3 thin films from elemental Bi and Te sources in high vacuum is presented. Three different kinds of substrates were used: Si (1 0 0), Si (1 1 1) and sapphire (0 0 1). Structural and morphological properties of the films were investigated by scanning electron microscopy, energy dispersive and Raman spectroscopies, high-resolution x-ray diffraction and atomic force microscopy. In optimal conditions, all the films showed preferential orientation with the c-plane perpendicular to the growth direction, however the a-plane orientation was found to be clearly dependent on the substrate used: samples grown on sapphire grew coherently with the substrate following a spiral growth mechanism in a pyramidal structure.