Lateral and Vertical Two-Dimensional Layered Topological Insulator Heterostructures

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Heterostructured configurations of 2D semiconductor materials allow for band gap engineering and novel device design.
• Previous synthesis of 2D topological insulators (TIs) like Bi2Se3, Bi2Te3, and Sb2Te3 lacked spatial control for lateral heterostructures.

Purpose of the Study:

• To report an in situ two-step synthesis process for fabricating 2D TI lateral heterostructures with spatial control.
• To investigate the growth mechanism and electrical properties of these heterostructures.

Main Methods:

• In situ two-step synthesis.
• Scanning transmission electron microscopy (STEM) and energy-dispersive X-ray (EDX) mapping.
• Ex situ atomic force microscopy (AFM).
• Electrical transport measurements.

Main Results:

• Successful spatial control of chemical composition in 2D TI lateral heterostructures.
• Identification of an edge-induced growth mechanism.
• Demonstration of p-n junctions in Bi2Te3/Sb2Te3 heterostructures.

Conclusions:

• The developed synthesis method enables controlled fabrication of 2D TI lateral heterostructures.
• These heterostructures exhibit functional p-n junctions, indicating potential for advanced electronic applications.