Experimental realization of a topological p-n junction by intrinsic defect-grading

TL;DR

This paper reports the experimental creation of topological p-n junctions in Bi2Te3 with narrow widths and a built-in potential, enabling exploration of their unique physics and potential applications.

Contribution

We demonstrate a method to intrinsically form topological p-n junctions via defect grading in Bi2Te3, a significant step forward in topological insulator device research.

Findings

Topological p-n junctions as narrow as a few tenths of nm.

Built-in potential of 110 meV across the junction.

Bi2Te3 as a reliable platform for topological p-n junction studies.

Abstract

A junction between an n- and p-type semiconductor results in the creation of a depletion region whose properties are at the basis of nowadays electronics. If realized using topological insulators as constituent materials, p-n junctions are expected to manifest several unconventional effects with great potential for applications. Experimentally, all these fascinating properties remained unexplored so far, mainly because prototypical topological PNJs, which can be easily realized and investigated, were not readily available. Here, we report on the creation of topological PNJs which can be as narrow as few tenths of nm showing a built-in potential of 110meV. These junctions are intrinsically obtained by a thermodynamic control of the defects distribution across the crystal. Our results make Bi2Te3 a robust and reliable platform to explore the physics of topological p-n junction.