TY - JOUR
T1 - Growth of Twin-Free and Low-Doped Topological Insulators on BaF2(111)
AU - Bonell, Frédéric
AU - González Cuxart, Marc
AU - Song, Kenan
AU - Robles, Roberto
AU - Ordejón, Pablo
AU - Roche, Stephan
AU - Mugarza, Aitor
AU - Valenzuela, Sergio O.
PY - 2017/9/6
Y1 - 2017/9/6
N2 - © 2017 American Chemical Society. We demonstrate the growth of twin-free Bi2Te3 and Sb2Te3 topological insulators by molecular beam epitaxy and a sizable reduction of the twin density in Bi2Se3 on lattice-matched BaF2(111) substrates. Using X-ray diffraction, electron diffraction and atomic force microscopy, we systematically investigate the parameters influencing the formation of twin domains and the morphology of the films, and show that Se- and Te-based alloys differ by their growth mechanism. Optimum growth parameters are shown to result in intrinsically low-doped films, as probed by angle-resolved photoelectron spectroscopy. In contrast to previous approaches in which twin-free Bi2Se3 films are achieved by increasing the substrate roughness, the quality of our Bi2Te3 is superior on the flattest BaF2 substrates. This finding indicates that, during nucleation, the films not only interact with the topmost atomic substrate layer but also with buried layers that provide the necessary stacking information to promote a single twin, an observation that is supported by ab initio calculations.
AB - © 2017 American Chemical Society. We demonstrate the growth of twin-free Bi2Te3 and Sb2Te3 topological insulators by molecular beam epitaxy and a sizable reduction of the twin density in Bi2Se3 on lattice-matched BaF2(111) substrates. Using X-ray diffraction, electron diffraction and atomic force microscopy, we systematically investigate the parameters influencing the formation of twin domains and the morphology of the films, and show that Se- and Te-based alloys differ by their growth mechanism. Optimum growth parameters are shown to result in intrinsically low-doped films, as probed by angle-resolved photoelectron spectroscopy. In contrast to previous approaches in which twin-free Bi2Se3 films are achieved by increasing the substrate roughness, the quality of our Bi2Te3 is superior on the flattest BaF2 substrates. This finding indicates that, during nucleation, the films not only interact with the topmost atomic substrate layer but also with buried layers that provide the necessary stacking information to promote a single twin, an observation that is supported by ab initio calculations.
U2 - 10.1021/acs.cgd.7b00525
DO - 10.1021/acs.cgd.7b00525
M3 - Article
SN - 1528-7483
VL - 17
SP - 4655
EP - 4660
JO - Crystal Growth and Design
JF - Crystal Growth and Design
IS - 9
ER -