Tuning band alignment at a semiconductor-crystalline oxide heterojunction via electrostatic modulation of the interfacial dipole

Chrysler, M.; Gabel, J.; Lee, T. -L.; Penn, A. N.; Matthews, B. E.; Kepaptsoglou, D. M.; Ramasse, Q. M.; Paudel, J. R.; Sah, R. K.; Grassi, J. D.; Zhu, Z.; Gray, A. X.; LeBeau, J. M.; Spurgeon, S. R.; Chambers, S. A.; Sushko, P. V.; Ngai, J. H.

doi:10.1103/physrevmaterials.5.104603

DOE OSTI · 1843241

Tuning band alignment at a semiconductor-crystalline oxide heterojunction via electrostatic modulation of the interfacial dipole

Chrysler, M.·Gabel, J.·Lee, T. -L.·Penn, A. N.·Matthews, B. E.·Kepaptsoglou, D. M.·Ramasse, Q. M.·Paudel, J. R.·Sah, R. K.·Grassi, J. D.·Zhu, Z.·Gray, A. X.·LeBeau, J. M.·Spurgeon, S. R.·Chambers, S. A.·Sushko, P. V.·Ngai, J. H.

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Abstract

In this paper, we demonstrate that the interfacial dipole associated with bonding across the SrTiO 3 /Si heterojunction can be tuned through space charge, thereby enabling the band alignment to be altered via doping. Oxygen impurities in Si act as donors that create space charge by transferring electrons across the interface into SrTiO 3 . The space charge induces an electric field that modifies the interfacial dipole, thereby tuning the band alignment from type II to III. The transferred charge, accompanying built-in electric fields, and change in band alignment are manifested in electrical transport and hard x-ray photoelectron spectroscopy measurements. Ab initio models reveal the interplay between polarization and band offsets. We find that band offsets can be tuned by modulating the density of space charge across the interface. Modulating the interface dipole to enable electrostatic altering of band alignment opens additional pathways to realize functional behavior in semiconducting hybrid heterojunctions.

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Chrysler, M., Gabel, J., Lee, T. -L., Penn, A. N., Matthews, B. E., Kepaptsoglou, D. M., Ramasse, Q. M., Paudel, J. R., Sah, R. K., Grassi, J. D., Zhu, Z., Gray, A. X., LeBeau, J. M., Spurgeon, S. R., Chambers, S. A., Sushko, P. V., Ngai, J. H.. 2021-10-08. Tuning band alignment at a semiconductor-crystalline oxide heterojunction via electrostatic modulation of the interfacial dipole. https://doi.org/10.1103/physrevmaterials.5.104603

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