Fermi level pinning and band bending in δ -doped BaSnO3

Abstract

Various δ-doped semiconductor heterostructures have been effectively used for devices at room temperature and for quantum phenomena at low temperatures. Here, we use BaSnO3 and investigate its δ-doped system, focusing on its band bending and surface boundary conditions. We measured the two-dimensional carrier density (n2D) of the δ-doped BaSnO3 system of various thicknesses and doping levels. We also studied the effect of the BaSnO3 capping layer thickness on n2D. We show that the δ-doped BaSnO3 system can be very well described by band bending with the aid of the Poisson-Schrödinger simulation. At the same time, the capping layer thickness dependence of n2D reveals how the boundary condition on the surface of La-doped BaSnO3 evolves as a function of its capping layer thickness.