High Mobility Two-Dimensional Electron Gas at the BaSnO3/SrNbO3 Interface

Sharad Mahatara; Suresh Thapa; Hanjong Paik; Ryan Comes; Boris Kiefer

doi:10.1021/acsami.2c12195

High Mobility Two-Dimensional Electron Gas at the BaSnO₃/SrNbO₃ Interface

ACS Appl Mater Interfaces. 2022 Oct 5;14(39):45025-45031. doi: 10.1021/acsami.2c12195. Epub 2022 Sep 23.

Authors

Sharad Mahatara¹, Suresh Thapa², Hanjong Paik^{3

4}, Ryan Comes², Boris Kiefer¹

Affiliations

¹ Department of Physics, New Mexico State University, 1255 N Horseshoe, Las Cruces, New Mexico 88003-8001, United States.
² Department of Physics, Auburn University, 380 Duncan Drive, Auburn, Alabama 36849, United States.
³ Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM), Cornell University, 210 Bard Hall, Ithaca, New York 14853, United States.
⁴ School of Electrical & Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States.

PMID: 36149756
DOI: 10.1021/acsami.2c12195

Abstract

Oxide two-dimensional electron gases (2DEGs) promise high charge carrier concentrations and low-loss electronic transport in semiconductors such as BaSnO₃ (BSO). ACBN0 computations for BSO/SrNbO₃ (SNO) interfaces show Nb-4d electron injection into extended Sn-5s electronic states. The conduction band minimum consists of Sn-5s states ∼1.2 eV below the Fermi level for intermediate thickness 6-unit cell BSO/6-unit cell SNO superlattices, corresponding to an electron density in BSO of ∼10²¹ cm^-3. Experimental studies of analogous BSO/SNO interfaces grown by molecular beam epitaxy confirm significant charge transfer from SNO to BSO. In situ angle-resolved X-ray photoelectron spectroscopy studies show an electron density of ∼4 × 10²¹ cm^-3. The consistency of theory and experiments show that BSO/SNO interfaces provide a novel materials platform for low loss electron transport in 2DEGs.

Keywords: 2DEGS; charge transfer; conduction band minimum; electron density; heterostructure.