Fast Switching of Bolometric and Self‐Powered Effects in 2H‐NbSe₂ for High‐Efficiency Low‐Energy Photon Harvesting

Abstract The high‐performance detector that operates at the low‐photon‐energy range (≈meV) of the electromagnetic spectrum at room temperature remains in urgent demand for application in a variety of important sectors, including 6G communications, security, sensing, medicine, space science, etc. The vast range of 2D‐layered nanomaterials and their distinct layer structures provide an ideal foundation for the manufacture of sophisticated photodetectors and detectors with convenient fabrication methods. In this paper, the direct detection of terahertz waveband dominated by the bolometer effect and photo‐thermoelectric effect is demonstrated, which is endowed with a versatile integration of 2H‐NbSe₂ in terms of planar and vertical van der Waals structures. This 2H‐NbSe₂‐based device can detect broadband long wavelength due to the bolometer effect, and the van der Waals heterostructure‐based device exhibits excellent sensitivity and self‐powered photo‐thermoelectric conversion with high responsivity (>735 V W⁻¹), low response time (<1 µs), as well as low noise equivalent power (NEP < 50 pW Hz^−0.5) at room temperature. The photodetector engineers versatile detection mechanisms, displaying low‐energy photons on the hybrid integration of novel low‐dimensional materials and providing an opportunity for the practical application of energy harvesting.