QUANTUM TUNNELING NEMS

Quantum tunneling is an exceedingly sensitive probe of inter-electrode separation, electrode area, the type of electrode material and the nature of intervening insulator. Our devices are based on variable overlap area of the quasi 1D–nanowires1,2, electrodes placed on two opposing atomically flat surfaces. A generic nanoTrek® device is composed of two plates separated by a very thin layer of insulator, e.g. soft-matter spacer, air, vacuum. Several hundred to many thousands quasi-1D nanowires are deposited on each plate. The device can be thought of as a 2D plate/insulating layer (liquid)/ 2D plate sandwich. The nanowires on the two opposing surfaces facing each other and aligned with each other form elongated electrodes in the tunneling process. We have built and successfully tested devices composed of two individual Si chips separated with monolayer of soft-matter spacer (3,4,5)
In this poster we describe the concept leading to 3D monolithic nanoTrek® device specifically suited for sensing dynamic quantities. Both 2D substrates are part of one monolithic unit. One plate is suspended on etched beams. Depending on desired functionality or performance there can be one to four beams with width-to-length-to-thickness ratios designed for specific device sensitivity. Nanowires are fabricated on the top surface of the larger, bottom plate and, opposing them, at the bottom surface of a movable, top plate. Separation between the plates is in the range of 1–10 nm. We discuss several different candidate processes suitable for fabrication of our monolithic devices.