Modulating and stabilizing MoS2 electronics via a sulfur capping layer

Two-dimensional semiconductors, featuring atomic-scale thickness, excellent electrostatic gate control, and outstanding electrical properties, hold great promise for next-generation electronics. Recently, monolayer MoS2, a typical two-dimensional semiconductor, has been extensively explored for field-effect transistors (FETs). However, its atomically thin channel is highly sensitive to environmental exposure and interfacial perturbations, leading to significant performance degradation. Here, we report a low-temperature (200 °C), intrinsic sulfur passivation strategy to form a nondestructive capping layer on monolayer MoS2 FETs. This capping layer effectively isolates the channel from ambient species while passivating sulfur vacancy defects. As a result, the electrical performance is markedly improved, leading to a positive threshold voltage shift of 1.5 V and a substantial reduction in hysteresis from 2 V to 160 mV. Notably, the devices exhibit excellent environmental stability, maintaining their performance after 180 days under ambient conditions. Based on this approach, rail-to-rail inverters are realized using a pristine MoS2 load transistor and an S-capped MoS2 driver transistor, achieving a high voltage gain of 175.11 with symmetric noise margins (noise margin high ≈ 1.82 V and noise margin low ≈ 1.82 V). Importantly, large-scale inverter arrays demonstrate excellent device uniformity and reproducibility in performance. Furthermore, the scalability of this strategy is demonstrated via various fundamental logic circuits, including NOR and NAND gates, as well as a five-stage ring oscillator. These results highlight the effectiveness of sulfur passivation in enabling high-performance, stable, and scalable MoS2-based electronic and integrated circuit applications.