  As a unique perovskite transparent oxide semiconductor, high-mobility
La-doped BaSnO3 films have been successfully synthesized by molecular beam
epitaxy and pulsed laser deposition. However, it remains a big challenge for
magnetron sputtering, a widely applied technique suitable for large-scale
fabrication, to grow high-mobility La-doped BaSnO3 films. Here, we developed a
method to synthesize high-mobility epitaxial La-doped BaSnO3 films (mobility up
to 121 cm2V-1s-1 at the carrier density ~ 4.0 x 10^20 cm-3 at room temperature)
directly on SrTiO3 single crystal substrates using high-pressure magnetron
sputtering. The structural and electrical properties of the La-doped BaSnO3
films were characterized by combined high-resolution X-ray diffraction, X-ray
photoemission spectroscopy, and temperature-dependent electrical transport
measurements. The room temperature electron mobility of La-doped BaSnO3 films
in this work is 2 to 4 times higher than the reported values of the films grown
by magnetron sputtering. Moreover, in the high carrier density range (n > 3 x
10^20 cm-3), the electron mobility value of 121 cm2V-1s-1 in our work is among
the highest values for all reported doped BaSnO3 films. It is revealed that
high argon pressure during sputtering plays a vital role in stabilizing the
fully relaxed films and inducing oxygen vacancies, which benefit the high
mobility at room temperature. Our work provides an easy and economical way to
massively synthesize high-mobility transparent conducting films for transparent
electronics.
