Fig. 1: Structure of Modulation-doped VO2 heterostructures.
a Schematic diagram of the heterostructures used in this work. The thickness of VO2 is varied while the thicknesses of all the other layers are as mentioned in the schematic. b Schematic energy band diagram for a VO2/LAO/TiO2-x heterostructure before and after the junction formation. Electron accumulation is expected based on the known band offsets. The color intensities are chosen to be proportional to expected electron densities for better visualization. EC, EV, and EF indicate the conduction band edge, valence band edge, and Fermi level, respectively. c High-resolution cross-sectional high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image showing abrupt interfaces between TiO2 substrate and VO2 film and VO2 film and the amorphous LAO spacer layer. d Elemental mapping using energy dispersive x-ray spectroscopy (EDS) showing the various layers in the heterostructure. Note that the scales of c and d are different.
