Fluorinated CYTOP passivation effects on the electrical reliability of multilayer MoS₂ field-effect transistors

We demonstrated highly stable multilayer molybdenum disulfide (MoS₂) field-effect transistors (FETs) with negligible hysteresis gap (ΔV _HYS ∼ 0.15 V) via a multiple annealing scheme, followed by systematic investigation for long-term air stability with time (∼50 days) of MoS₂ FETs with (or without) CYTOP encapsulation. The extracted lifetime of the device with CYTOP passivation in air was dramatically improved from 7 to 377 days, and even for the short-term bias stability, the experimental threshold voltage shift, outstandingly well-matched with the stretched exponential function, indicates that the device without passivation has approximately 25% larger the barrier distribution (ΔE _B = k _B T _o) than that of a device with passivation. This work suggests that CYTOP encapsulation can be an efficient method to isolate external gas (O₂ and H₂O) effects on the electrical performance of FETs, especially with low-dimensional active materials like MoS₂. (paper)