A method of forming an electrical device that includes forming ohmic contacts to a type III-V semiconductor substrate, and depositing a dielectric layer on the ohmic contacts and an exposed surface of the type III-V semiconductor substrate. A nanotube is positioned on a surface of the high-k dielectric that is overlying the type III-V semiconductor substrate and is between the ohmic contacts using chemical recognition. The dielectric layer is removed so that the nanotube is repositioned directly on the type III-V semiconductor substrate to provide an Schottky contact to a channel region of the type III-V semiconductor substrate.