Investigating Laser-Induced Phase Engineering in MoS₂ Transistors

Phase engineering of MoS₂ transistors has recently been demonstrated and has led to record low contact resistances. The phase patterning of MoS₂ flakes with laser radiation has also been realized via spectroscopic methods, which invites the potential of controlling the metallic and semiconducting phases of MoS₂ transistors by simple light exposure. Nevertheless, the fabrication and demonstration of laser-patterned MoS₂ devices starting from the metallic polymorph have not been demonstrated yet. Here, we study the effects of laser radiation on 1T/1T′$-MoS₂ transistors with the prospect of driving an in situ phase transition to the 2H-polymorph through light exposure. We find that although the Raman peaks of 2H-MoS₂ become more prominent and the ones from the 1T/1T$′ phase fade after the laser exposure, the semiconducting properties of the laser-patterned devices are not fully restored, and the laser treatment ultimately leads to the degradation of the transport channel.