Interface passivation and trap reduction via hydrogen fluoride for molybdenum disulfide on silicon oxide back-gate transistors

Layered semiconductor molybdenum disulfide (MoS₂) has recently emerged as a promising material for flexible electronic and optoelectronic devices because of its finite bandgap and high degree of gate control. Here, we report a hydrogen fluoride (HF) passivation technique for improving the carrier mobility and interface quality of chemical vapor deposited monolayer MoS₂ on a SiO₂/Si substrate. After passivation, the fabricated MoS₂ back-gate transistors demonstrate a more than double improvement in average electron mobility, a reduced gate hysteresis gap of 3 V, and a low interface trapped charge density of ∼5.8 × 10¹¹ cm⁻². The improvements are attributed to the satisfied interface dangling bonds, thus a reduction of interface trap states and trapped charges. Surface x-ray photoelectron spectroscopy analysis and first-principles simulation were performed to verify the HF passivation effect. The results here highlight the necessity of a MoS₂/dielectric passivation strategy and provides a viable route for enhancing the performance of MoS₂ nano-electronic devices. (paper)