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

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.

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Cited by in corpus (3)

• Quantum Transport and Potential of Topological States for Thermoelectricity in Bi${}_2$Te${}_3$ Thin Films
• Highly superlinear photogalvanic effects in (Bi${}_{0.3}$Sb${}_{0.7}$)${}_2$(Te${}_{0.1}$Se${}_{0.9}$)${}_3$: Probing 3D topological insulator surface states at room temperature
• Tracing Dirac points of topological surface states by ferromagnetic resonance