Multispectral Integrated\nBlack Arsenene Phototransistors\nfor High-Resolution Imaging and Enhanced Secure Communication

The demand for broadband, room-temperature infrared,\nand terahertz\n(THz) detectors is rapidly increasing owing to crucial applications\nin telecommunications, security screening, nondestructive testing,\nand medical diagnostics. Current photodetectors face significant challenges,\nincluding high intrinsic dark currents and the necessity for cryogenic\ncooling, which limit their effectiveness in detecting low-energy photons.\nHere, we introduce a high-performance ultrabroadband photodetector\noperating at room temperature based on two-dimensional black arsenene\n(b-As) nanosheets. This device demonstrates responsivity across visible,\nnear-infrared, and THz spectral ranges, with responsivities reaching\n91.6 A/W at 520 nm, 6.3 A/W at 1550 nm, and 7.8 V/W at 0.27 THz. The\nexceptional THz responsivity is attributed to the use of plasma-wave\nrectification in antenna-integrated field-effect transistors with\nasymmetric antennas, enhancing light-matter interaction and facilitating\nnonlinear rectification within the two-dimensional electron gas of\nthe transistor channel, achieving a voltage-dependent bipolar response.\nThese advanced b-As-based photodetectors also enable secure THz communication\nthrough complex logic operations, achieving robust data encryption\nand high-performance signal processing.