Within the framework of 2D materials, we present four theoretical models of a vertical field-effect transistor (FET) composed of simple alternate graphene and MoS2 layers. The electronic transport properties at a specific graphene/MoS2 interface in each configuration are investigated by focusing in particular on the current as a function of the gate voltage. The gate voltage, simulated with a shift of the bands of a specific layer, allows us to tune the current at the interface and the charge transfer between the planes. This analysis of the charge transfer as a function of the gate voltage reveals a strong connection with the transport characteristics as the slope of the current curve. The analysis of physical phenomena at the graphene/MoS2 interface can further improve the 2D vertical FET performance and contribute to the development of new 2D nanotechnology.