paper

Transport properties of band engineered p-n heterostructures of epitaxial Bi $_{2}$ Se $_{3}$ /(Bi $_{1 - x}$ Sb $_{x}$ ) $_{2}$ (Te $_{1 - y}$ Se $_{y}$ ) $_{3}$ topological insulators

arXiv:2010.06532 · doi:10.1103/PhysRevMaterials.5.014202

Abstract

The challenge of parasitic bulk doping in Bi-based 3D topological insulator materials is still omnipresent, especially when preparing samples by molecular beam epitaxy (MBE). Here, we present a heterostructure approach for epitaxial BSTS growth. A thin n-type Bi $_{2}$ Se $_{3}$ (BS) layer is used as an epitaxial and electrostatic seed which drastically improves the crystalline and electronic quality and reproducibility of the sample properties. In heterostructures of BS with p-type (Bi $_{1 - x}$ Sb $_{x}$ ) $_{2}$ (Te $_{1 - y}$ Se $_{y}$ ) $_{3}$ (BSTS) we demonstrate intrinsic band bending effects to tune the electronic properties solely by adjusting the thickness of the respective layer. The analysis of weak anti-localization features in the magnetoconductance indicates a separation of top and bottom conduction layers with increasing BSTS thickness. By temperature- and gate-dependent transport measurements, we show that the thin BS seed layer can be completely depleted within the heterostructure and demonstrate electrostatic tuning of the bands via a back-gate throughout the whole sample thickness.

Transport properties of band engineered p-n heterostructures of epitaxial Bi2​Se3​/(Bi1−x​Sbx​)2​(Te1−y​Sey​)3​ topological insulators

Abstract

Transport properties of band engineered p-n heterostructures of epitaxial Bi $_{2}$ Se $_{3}$ /(Bi $_{1 - x}$ Sb $_{x}$ ) $_{2}$ (Te $_{1 - y}$ Se $_{y}$ ) $_{3}$ topological insulators