Single‐Orientation Epitaxy of Quasi‐1D Tellurium Nanowires on M‐Plane Sapphire for Highly Uniform Polarization Sensitive Short‐Wave Infrared Photodetection

Abstract

AbstractTellurium (Te), an elemental van der Waals semiconductor, has intriguing anisotropic physical properties owing to its inherent quais‐1D crystal structure. Synthesizing ultrathin Te crystal with uniform orientation is important to its large‐scale device applications, but that remains a great challenge. Herein, the nanoscale grooves‐induced unidirectional epitaxy growth of 1D Te nanowires via physical vapor deposition on the annealed m‐plane sapphire is demonstrated. By enhancing the annealing temperature from 1000 to 1300 °C, nanoscale grooves on m‐plane sapphire arising along the [100] direction and gradually distinct, and the corresponding Te nanowires grown on them turns from random to uniform, finally achieving nearly 95% unidirectional Te nanowires. The as‐grown Te nanowires possess high crystallinity with clearly chiral helical chains along the c‐axis direction and reveal thickness‐tunable bandgap with prominent linear‐dichroic. As results, the Te nanowire‐based photodetectors demonstrate a broadband photoresponse from visible (532 nm) to short‐wave infrared (2530 nm), with high responsivity of 327 A W−1 as well as strong and uniform polarization sensitivity (anisotropic ratio = 2.05) to 1550 nm light. The high crystallinity and superior anisotropy of Te nanowires, combined with the orientation‐controlled preparation endows it with great feasibility for constructing chip‐scale multifunctional optoelectronic devices.