Perovskite stannates $\mathrm{BaSn}{\mathrm{O}}_3$ (BSO) and $\mathrm{SrSn}{\mathrm{O}}_3$ (SSO) have attracted significant interest due to their large electron mobility and wide optical band gaps. Here, we discuss the design and characterization of a BSO/$\mathrm{SrTi}{\mathrm{O}}_3$ quantum well (QW) with an $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$ barrier that takes advantage of the small effective mass of $\mathrm{BaSn}{\mathrm{O}}_3$ ($0.19m_e)$ and a large conduction band offset to $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$ (2.5 eV) that provides strong confinement. This structure is a prototype implementation of a high-mobility all-oxide QW design. We find good agreement between the band alignment obtained from first-principles calculations and photoemission measurements. Informed by this, we calculate subband energies using a Poisson-Schrödinger (PS) solver to design and subsequently fabricate QWs using oxide molecular beam epitaxy. Ellipsometry analysis of QWs with three different BSO thicknesses confirmed the shift of the absorption edge of the heterostructure, in good agreement with results from the PS solver, thus confirming quantum confinement. The fabrication of transition metal oxide deep QW devices opens possibilities for advanced functionalities in electro-optical applications.

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• Photonics
• Heterostructures
• Perovskites
• Optical spectroscopy