Morphology Control in van der Waals Epitaxy of Bismuth Telluride Topological Insulators

Abstract

Bismuth telluride have regained significant attention as a prototype of topological insulator. Thin films of high quality have been investigated as a basic platform for novel spintronic devices. Low mobility of bismuth and high desorption coefficient of telluride compose a scenario where growth parameters have drastic effects on structural and electronic properties of the films. Recently [J. Phys. Chem. C 2019, 123, 24818−24825], a detailed investigation has been performed on the dynamics of defects in epitaxial films of this material, revealing the impact of film/substrate lattice misfit on the films’ lateral coherence. Very small lattice misfit (<0.05%) are expected to have no influence on quality of epitaxial system with atomic layers weakly bonded to each other by van der Waals forces, contrarily to what was observed. In this work, we investigate the correlation between lattice misfit and size and morphology of the film crystalline domains. Three-dimensional reciprocal-space maps of film Bragg reflections obtained with synchrotron X-rays are used to visualize the spatial conformation of the crystallographic domains through film thickness, while atomic force microscopy images provide direct information of the domains morphology at the film surface.

Quantum transport and potential of topological states for thermoelectricity in Bi2Te3 thin films

“…For samples grown on STO with the two-step method as well, the optimal temperature for the nucleation layer is also 170 °C, whereas for the second layer it is 250 °C. Figures 2(a)-(d) demonstrates the improvement of the surface morphology as T sub is increased for four different samples of 15 nm Bi 2 Te 3 grown on STO [99].…”

“…Different studies have investigated the correlation between surface morphology and structural defects of epitaxial Bi 2 Te 3 films grown on different substrates, which demonstrated that such defects depend strongly on the substrate material and growth conditions [99,[111][112][113].…”

Quantum Transport and Potential of Topological States for Thermoelectricity in Bi$_2$Te$_3$ Thin Films

“…Different studies have investigated the correlation between surface morphology and structural defects of epitaxial Bi 2 Te 3 films grown on different substrates, which demonstrated that such defects depend strongly on the substrate material and growth conditions [109][110][111][112].…”

X-ray diffraction tools for structural modeling of epitaxic films of an intrinsic antiferromagnetic topological insulator

“…However, the weakness of vdW interlayer forces lead in general to systems undergoing drastic changes as a function of subtle variation in growth conditions. Finding controllable fabrication processes of such systems has proven challenging [12,13]. On top of this, the recently discovered intrinsic magnetic topological insulator MnBi 2 Te 4 has added a new chapter to the phenomenological exploration of combining non-trivial electronic band topology and magnetism.…”