Selective Growth of Type‐II Weyl‐Semimetal and Van der Waals Stacking for Sensitive Terahertz Photodetection

Abstract

AbstractThe emergence of novel topological semimetal materials, accompanied by exotic non‐equilibrium properties, not only provides a fertile playground for a fundamental level of interest but also opens exciting opportunities for inventing new applications by making use of different light‐induced effects such as nonlinear optics, optoelectronics, especially for the highly pursued terahertz (THz) technology due to the gapless electronic structures. Exploring type‐II Weyl semimetal endowed with the richness of quantum wavefunction and peculiar band structure, underlie strong nonlinear coupling with THz waves. Here, the selective growth of type‐II Weyl semimetal NbIrTe4 by means of a self‐flux approach is reported, which hosts strongly tilted Weyl cones and exotic Fermi arcs. The oscillating THz field induced by the antenna is engineered in terms of planar metal‐topological semimetal‐metal structure, along with van der Waals stacking, which allows for self‐powered photodetection at room temperature. The results elucidate the superior performance of NbIrTe4‐graphene heterostructure‐based photodetectors with responsivity up to 264.6 V W−1 at 0.30 THz, fast response of 1 µs as well as low noise equivalent power ˂0.28 nW Hz−0.5 is achieved, already exhibiting high‐quality imaging at THz frequency. The results promise superb impacts in exploring topological Weyl semimetals for efficient low‐energy photon harvesting.