We explore the relationship between bond formation at the free surface and buried interface of the epitaxial SrTiO3(001)/p-Ge(001) heterojunction and the associated valence and conduction band offsets. We observe clear broadening in the Ge 3d and Sr 3d core-level x-ray photoelectron spectra relative to those for surfaces of pure Ge and SrTiO3. Although such broadening could in principle be indicative of built-in potential drops on both side of the heterojunction, it is driven by chemical shifts at the surface and interface. The impact of these two interpretations of spectral broadening on band alignment is significant, amounting to a 0.3 eV difference in valence band offset.
Revised: December 28, 2018 |
Published: February 24, 2017
Citation
Chambers S.A., Y. Du, R.B. Comes, S.R. Spurgeon, and P.V. Sushko. 2017.The effects of core-level broadening in determining band alignment at the epitaxial SrTiO3(001)/p-Ge(001) heterojunction.Applied Physics Letters 110, no. 8:082104.PNNL-SA-123225.doi:10.1063/1.4977422