Dopant-site-dependent scattering by dislocations in epitaxial films of perovskite semiconductor BaSnO₃

We studied the conduction mechanism in Sb-doped BaSnO₃ epitaxial films, and compared its behavior with that of the mechanism of its counterpart, La-doped BaSnO₃.We found that the electron mobility in BaSnO ₃ films was reduced by almost 7 times when the dopant was changed from La to Sb, despite little change in the effective mass of the carriers. This indicates that the scattering rate of conduction electrons in theBaSnO ₃ system is strongly affected by the site at which the dopants are located. More importantly,we found that electron scattering by threading dislocations also depends critically on the dopant site. We propose that the large enhancement of scattering by the threading dislocations in Sb-doped BaSnO₃ films is caused by the combination effect of the change in the distribution of Sb impurities in the films, the formation of the Sb impurity clusters near the threading dislocations, and the conduction electron clustering near the Sb impurities.