Electronic Structure and Epitaxy of CdTe Shells on InSb Nanowires

TL;DR

This study investigates the electronic properties and epitaxial growth of CdTe shells on InSb nanowires, revealing potential for device applications through favorable band alignment and high-quality epitaxy.

Contribution

It provides the first detailed analysis of InSb-CdTe interfaces, showing type-I band alignment and defect-free epitaxial growth of CdTe on InSb nanowires.

Findings

Type-I band alignment with small conduction band offset.

Epitaxial growth of defect-free CdTe shells on InSb nanowires.

No significant impact on nanowire mobility from CdTe coating.

Abstract

Indium antimonide (InSb) nanowires are used as building blocks for quantum devices because of their unique properties, i.e., strong spin-orbit interaction and large Land\'e g-factor. Integrating InSb nanowires with other materials could potentially unfold novel devices with distinctive functionality. A prominent example is the combination of InSb nanowires with superconductors for the emerging topological particles research. Here, we combine the II-VI cadmium telluride (CdTe) with the III-V InSb in the form of core-shell (InSb-CdTe) nanowires and explore potential applications based on the electronic structure of the InSb-CdTe interface and the epitaxy of CdTe on the InSb nanowires. We determine the electronic structure of the InSb-CdTe interface using density functional theory and extract a type-I band alignment with a small conduction band offset ($\leq$ 0.3 eV). These results indicate the potential application of these shells for surface passivation or as tunnel barriers in combination with superconductors. In terms of the structural quality of these shells, we demonstrate that the lattice-matched CdTe can be grown epitaxially on the InSb nanowires without interfacial strain or defects. These epitaxial shells do not introduce disorder to the InSb nanowires as indicated by the comparable field-effect mobility we measure for both uncapped and CdTe-capped nanowires.