The disclosed technology relates generally to semiconductor devices, and more particularly to field-effect transistors (FETs) comprising nanostructures, such as nanowires, fins, and two dimensional materials. In an aspect, a FET device comprises a substrate having an insulating surface and a vertical structure extending in a direction substantially perpendicular to the insulating surface, where the vertical structure has at least outer surfaces formed of an insulating material. The FET device additionally includes a thin layer of two-dimensional (2D) material enveloping the vertical structure and at least part of the insulating surface. The FET device additionally includes two electrodes in electrical contact with the thin layer of 2D material, where one of the electrodes is formed on top of the vertical structure. The FET device additionally includes a control electrode configured to apply an electric field across the thin layer of 2D material to cause a change in the conductivity of the thin layer of 2D material. The FET device further includes at least one stack of materials configured to provide different regions of band bending in the thin layer of 2D material by capacitive coupling.