Self-Powered Broadband Photodetection Driven by Asymmetric Surface Potential in Quasi-2D InAs Single Crystals.

Two-dimensional (2D) materials, with a tunable band structure, strong light-matter interaction, and unique carrier transport, are promising candidates for high-performance photodetectors. Here, high-quality InAs single crystals grown via van der Waals epitaxy coupled with an asymmetric metal-semiconductor structure enable efficient charge separation and photocurrent generation without external bias. Self-powered broadband photodetection based on quasi-2D InAs single crystals is demonstrated by breaking the inversion symmetry. At room temperature, the devices achieve a self-driven broadband photoresponse (300-1100 nm) with high responsivity (0.6 A/W), rapid rise/decay times (73.8/94 μs), and outstanding detectivity (2.3 × 1012 Jones) under zero bias. This work demonstrates that the asymmetric channel in quasi-2D InAs enables efficient charge separation, offering a promising route to high-performance self-powered photodetectors (SPPD).