Embodiments of the invention include a method for fabricating a semiconductor device, the resulting structure, and a method for using the resulting structure. A substrate is provided. A hard mask layer is patterned over at least a portion of the substrate. Regions of the substrate not protected by the hard mask are doped to form a source region and a drain region. The hard mask layer is removed. A dielectric layer is deposited on the substrate. An insulative layer is deposited on the dielectric layer. A nano-channel is created by etching a portion of the insulative layer which passes over the source region and the drain region.