Gate Tunable Superlinear Photoresponse in 2D Hf _0.5 Zr _0.5 S ₂ Alloyed Crystal

ABSTRACT

Defect engineering is essential for controlling optoelectronic processes in semiconductors, yet achieving dynamic and tunable nonlinear photoresponse remains a challenge. In this work, we realize gate‐programmable photoresponse nonlinearity in high‐quality ternary Hf _0.5 Zr _0.5 S ₂ single crystals. Unlike their binary counterparts, few‐layered Hf _0.5 Zr _0.5 S ₂ phototransistors exhibit broadly tunable superlinear photocurrent from the deep‐ultraviolet to the visible range. Such superlinear response stems from alloy‐induced deep‐level traps, which trigger a dual‐recombination process regulated by dynamic trap filling. Importantly, electrostatic gating can continuously modulate the recombination kinetics, enabling the exponent α to be tuned from sublinear (∼0.85) to strongly superlinear (∼3.95). Our results establish alloy ordering as an intrinsic defect‐engineering platform, providing a viable route toward customizable nonlinear photodetection for adaptive sensing and neuromorphic vision systems.