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P-type transition metal dichalcogenides (TMDCs) field-effect transistor (FET) with high performance is fundamental for the development of 2D electronic and optoelectronic devices. We achieve the effective p-type doping using toroidal-magnetic-field (TMF) controlled oxygen plasma on the six-layer MoS 2 . The bottom-gated MoS 2 FET shows a record current on-off ratio of 10 7 , a hole mobility of 115.2 cm 2 V −1 s −1 and a subthreshold swing of 137 mV dec −1 at room temperature. The high performance is attributed to the negligible lattice defects and high substitutional rate through restricting the energy of oxygen ions, which are demonstrated by Raman spectroscopy, photoluminescence spectroscopy and x-ray photoelectron spectroscopy. The excellent p-type conduction is also beneficial from enhancing the ratio of O + 2 ions in oxygen plasma by the TMF. First-principle calculations validate that O + 2 ions lead to a shallow acceptor level at 42.16 meV above the valance band maximum and extracting 1.0 electron from MoS 2 lattice. These findings provide a scheme for realizing 2D integrated circuit and excellent optoelectronic devices using MoS 2 and other homogeneous TMDCs.

Monolayer 2H-phase MoS2-based photodetectors exhibit high photon absorption but suffer from low photoresponse, which severely limits their applications in optoelectronic fields. The metallic 1T phase of MoS2, while transporting carriers faster, shows negligible response to visible light, which limits its usage in photodetectors. Herein, we propose an ultrafast-response MoS2-based photodetector having a channel that consists of a 2H-MoS2 sensitizing monolayer on top of 1T@2H-MoS2. The 1T@2H-MoS2 layer has a thickness of several nanometers and is a mixture of metallic 1T-MoS2 and semiconducting 2H-MoS2, imparting metal-like properties to the photodetector. Compared with the monolayer 2H-MoS2 photodetector, we observed a drastic increase in the photoresponse of the 2H-MoS2/1T@2H-MoS2 vertically stacked photodetector to a value of 1917 A W–1. Owing to the presence of metallic 1T-MoS2 within the metal-like 1T@2H-MoS2, the performance of the 2H-MoS2/1T@2H-MoS2 vertically stacked photodetector is voltage bias-modulated with an external quantum efficiency (EQE) of up to 448,384% and a specific detectivity of up to ∼1011 Jones. The higher carrier density and higher mobility of the 1T@2H-MoS2 layer explain the better bias-modulated performance. In addition, the interface between 2H-MoS2 and 1T@2H-MoS2 ensures fewer dangling bonds and reduced lattice mismatching. Thus, this study presents an exclusive vertically stacked MoS2-based photodetector that lays the foundation for the development of photodetectors exhibiting higher photoresponse.

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