Semimetallic Nb/Ta-Te phases with charge density wave for mid- and long-wave infrared detection

Abstract Charge density wave (CDW), which typically opens a narrow energy gap near the Fermi level, is highly sensitive to low-energy photon excitations, providing a compelling basis for infrared detectors. Here, we systematically investigated one-dimensional (1D) NbTe4 and TaTe4, as well as two-dimensional (2D) NbTe2 and TaTe2, from the binary Nb/Ta-Te systems for mid- and long-wave infrared detection. They all exhibit notable infrared photoresponse under zero-bias (self-powered) operation governed by the photothermoelectric effect. NbTe2, in particular, achieves detectivities of 1.64 × 108 and 1.29 × 108 Jones under illumination of 4 and 8.47 μm infrared lights, respectively. Using artificial intelligence, super-resolution reconstruction was realized to enhance images obtained from photodetector-based single-pixel imaging, laying an important foundation for computing-in-memory integration. This work highlights Nb/Ta-Te phases as promising candidates for infrared detectors, paving the way for next-generation room-temperature, low-power intelligent infrared optoelectronic systems.