Plasma treatment of MoS₂ field-effect transistors using solid-state fluorine source

Abstract Plasma treatment using a solid-state fluorine (F) source can mitigate the emission of F-containing gases into the environment. In this study, we investigated the processability of Ar-plasma-mediated F treatment using a polytetrafluoroethylene (PTFE) sheet as the F source. Surface treatment of two-dimensional (2D) semiconductor devices using this method resulted in an improvement in field-effect mobility and a reduction in hysteretic behavior. The prolonged treatment led to heavy p-doping, possibly owing to substitutional F doping. The treatment strength was controllable by the treatment time and sample position during the treatment. Placing the samples upstream resulted in a milder treatment compared to that positioned downstream. The controllability of the proposed method enables us to fine-tune the properties of devices based on 2D materials. The treatment elements could be controlled using sheets made of materials other than PTFE, indicating the broad applicability of this method.