  Three-dimensional (3D) topological insulators (TIs) are candidate materials
for various electronic and spintronic devices due to their strong spin-orbit
coupling and unique surface electronic structure. Rapid, low-cost preparation
of large-area TI thin films compatible with conventional semiconductor
technology is key to the practical applications of TIs. Here, we show that
wafer-sized Bi2Te3 family TI and magnetic TI films with decent quality and
well-controlled composition and properties can be prepared on amorphous SiO2/Si
substrates by magnetron cosputtering. The SiO2/Si substrates enable us to
electrically tune (Bi1-xSbx)2Te3 and Cr-doped (Bi1-xSbx)2Te3 TI films between
p-type and n-type behavior and thus study the phenomena associated with
topological surface states, such as the quantum anomalous Hall effect (QAHE).
This work significantly facilitates the fabrication of TI-based devices for
electronic and spintronic applications.
