Ever since the invention of the tunnel diodes by Leo Esaki in 1957, they have been the subject of numerous studies as building blocks for ultra-low power electronics and also as sub-cell connections in multi-junction solar cells. Tunneling field-effect transistors (TFETs) have attracted a lot of attention for ultra low-power electronic applications because of superior OFF-state performance. However, to date, TFETs suffer from poor-ON state currents which can be addressed by increasing the tunneling area and electric field. In this respect, radial nanowire heterostructures are attractive candidates for boosting the ON-state of T-FETs because the tunneling area is proportional to LchannelRNW. A core/shell geometry also enables the gate electric field to align with the internal junction field which may result in an improved SS.