Percolative phase transition in few-layered MoSe₂ field-effect transistors using Co and Cr contacts

The metal-to-insulator (MIT) phase transition in two-dimensional (2D) materials under the influence of a gating electric field has revealed interesting electronic transport phenomena. Although the mechanism of the MIT in 2D semiconductors is a topic under debate, our work addresses the tunable percolative phase transition in few-layered MoSe₂ field-effect transistors (FET) with various metallic contacts. Here, we attempted to understand the MIT through temperature-dependent electronic transport measurements under the influence of an applied gate voltage. We examined the phenomenon with devices using two different kinds of metal contacts: more conventional chromium (Cr) and ferromagnetic cobalt (Co). The temperature-dependent conductivity data showed insulating-to-metallic behavior as a function of increasing carrier density, which was analyzed by fitting the data to the theory of a percolative phase transition.