Lateral and Vertical Two-Dimensional Layered Topological Insulator Heterostructures.

The heterostructured configuration between two-dimensional (2D) semiconductor materials has enabled the engineering of the band gap and the design of novel devices. So far, the synthesis of single-component topological insulator (TI) 2D materials such as Bi2Se3, Bi2Te3, and Sb2Te3 has been achieved through vapor phase growth and molecular beam epitaxy; however, the spatial controlled fabrication of 2D lateral heterostructures in these systems has not been demonstrated yet. Here, we report an in situ two-step synthesis process to form TI lateral heterostructures. Scanning transmission electron microscopy and energy-dispersive X-ray mapping results show the successful spatial control of chemical composition in these as-prepared heterostructures. The edge-induced growth mechanism is revealed by the ex situ atomic force microscope measurements. Electrical transport studies demonstrate the existence of p-n junctions in Bi2Te3/Sb2Te3 heterostructures.