Remote Doping of the Two-Dimensional-Electron-Gas State at the LaInO3/BaSnO3 Polar Interface

We investigate the transport properties of a modified interface by intentionally inserting a nanometer-scale undoped BaSnO3 spacer layer at the LaInO3/Ba1-xLaxSnO3 interface, thereby creating remotely doped heterostructures. Both the carrier density (n(s)) and the Hall mobility (mu(H)) continuously decrease as the thickness of the BaSnO3 spacer layer at the interface increases, indicating a changing electron-density profile as a function of the spacer thickness. We find the behavior is consistent with the recently proposed "interface-polarization" model by self-consistent one-dimensional Poisson-Schrodinger calculations. The decrease of n s makes it difficult to see the effect of the spacer layer on the mobility in the remotely doped structures due to the simultaneous decrease of mu caused by the ineffective screening of the remote Coulomb scattering from ionized donors in addition to the threading dislocation scattering. Hence, we control the band bending continuously via the field effect with a fixed spacer-layer thickness, leading to observation of enhanced mobility (mu(FE)) in the remotely doped 2DEG heterostructures in spite of high-density threading dislocations acting as the background charged impurities.