Excitonic insulator powers room-temperature ultra-sensitive visible to terahertz detection

Abstract

Phase transitions induce significant changes in the electrical and photonic properties of materials. Ultra-sensitive photodetectors leveraging material phase transitions can be realized near the transition temperature. Photodetectors based on Ta₂NiSe₅, a room-temperature excitonic insulator phase transition material, exhibit exceptional performance from visible to terahertz frequencies. Specifically, in the terahertz range, the electronic bandwidth is 360 kHz, and the specific detectivity (D*) reaches 5.3 × 10¹¹ cm·Hz^1/2·W⁻¹. The van der Waals heterostructure of Ta₂NiSe₅/WS₂ further enhances performance.