Quantum transport in a gate-controlled p-n junction in 3-dimensional Dirac semimetal Cd3As2 nanostructures

Abstract

Dirac semimetals such as Cd3As2 have drawn significant interest owing to their distinctive linear band structure. Several studies investigate the intriguing physical phenomena and electronic properties of these materials. In this study, Cd3As2 nanowires were synthesized using vapor transport method and transferred to a highly doped p-silicon substrate where recessed bottom gates were initially fabricated. Tuning of the bottom gates resulted to the realization of four conductance regimes forming p-n junctions in the nanowire device. Measurements at high magnetic fields show the formation of quantum dot in the bipolar regime. We find that the electrostatic potentials by the bottom gates as well as the suppression of Klein tunneling by magnetic field serves as tunnel barriers for the quantum confinement. Further investigation by performing both two-terminal and four-terminal measurements, allows the determination of contact resistance as well as electron and hole mobility. The ease in tunability of Cd3As2 makes it a practical candidate for functional quantum devices that require precise control of carrier density.