Twist-Angle-Controlled Built-In Field Reversal Enables Programmable Self-Powered Photodetection in Low-Symmetry...

Interfacial electric fields govern charge separation in van der Waals photodetectors, yet they are typically modulated by electrostatic gates or ferroelectric interlayers, which introduce power consumption and stability challenges. Here, we show that the twist angle intrinsically controls interfacial electrostatics in a low-symmetry ReS₂/ReSe₂ heterostructure. Rotating the anisotropic crystal axes reconstructs the interfacial polarization landscape, leading to a reversal of the built-in electric field in the orthostacking configuration. This enables efficient self-powered photodetection with an on/off ratio of 10⁵ and a high responsivity. Twist-controlled electrostatic reconstruction further modulates carrier separation and anisotropic transport, transforming the polarization-dependent photocurrent from a two-lobed to an approximately four-lobed profile and enabling tunable polarization sensitivity. Moreover, the deterministic twist-angle-dependent photocurrent allows hardware-level encoding. These results establish twist engineering as an effective strategy for tailoring interfacial fields and multifunctional optoelectronic responses in low-symmetry van der Waals heterostructures.