Ultralow Electric and Photonic Noise MoS 2 Transistors for Noise‐Limited Multistate Readout

Two‐dimensional (2D) van der Waals (vdW) semiconductors offer a compelling route toward co‐integrated logic, memory, and optoelectronic sensing. However, their performance is often constrained by defect‐mediated contact resistance, and its impact on low‐frequency noise (LFN) and signal resolution remains under‐quantified. Here we demonstrate antimony (Sb)‐contact monolayer MoS 2 transistors that simultaneously deliver ultralow 1/ f noise and high phototransistor gain, offering high photonic resolution. Sb contacts exhibit reduced contact‐limited transport and lower contact‐related carrier fluctuations than Au‐contact reference devices, leading to near‐ohmic‐like injections and a reduced LFN. Furthermore, under illumination, the devices exhibit high photogating‐enabled responsivity (1.33 × 10 5 A/W) and detectivity (7.50 × 10 15 Jones) under the measurement conditions used in this work without a discernible illumination‐induced excess noise. Leveraging the exceptional ultralow‐noise and high‐gain characteristics of the Sb‐contact MoS 2 transistors, we provide an LFN‐to‐photonic‐resolution metric that translates fluctuation‐induced noise into information fidelity. This work translates contact engineering of vdW semiconductors into a direct lever for information‐fidelity‐limited 2D logic and optoelectronics.