  Topological insulators (TIs) are exotic materials which have topologically
protected states on the surface due to the strong spin-orbit coupling. However,
a lack of ordered growth of TI thin films on amorphous dielectrics and/or
insulators presents a challenge for applications of TI-junctions. We report the
growth of topological insulator Bi2Se3 thin films on amorphous SiO2 by
molecular beam epitaxy (MBE). To achieve the ordered growth of Bi2Se3 on
amorphous surface, the formation of other phases at the interface is suppressed
by Se passivation. Structural characterizations reveal that Bi2Se3 films are
grown along the [001] direction with a good periodicity by van der Waals
epitaxy mechanism. Weak anti-localization effect of Bi2Se3 films grown on
amorphous SiO2 shows modulated electrical property by the gating response. Our
approach for ordered growth of Bi2Se3 on amorphous dielectric surface presents
considerable advantages for TI-junctions with amorphous insulator or dielectric
thin films.
