Gate controllable spin transistor with semiconducting tunneling barrier

In this work, we have fabricated a single layer graphene spin transistor on SiO₂/Si with a semiconducting tri-layer MoS₂ as the tunneling barrier between the ferromagnetic electrodes and the graphene channel. The spin transport in this parallel heterostructure were investigated in detail. The spin switch signal was controlled by tuning the conductivity of MoS₂ with different gate voltages. When MoS₂ was turned off under negative back gate voltage, the spin switch signal was clearly obtained, whereas it disappeared when MoS₂ was conductive under positive back gate bias. This spin transistor showed on, subthreshold and off states when back gate voltage changed from negative to positive. This work exploited a new possibility of semiconducting 2D materials as the tunneling barrier of spin valves.